# rss_item

guid: tag:blogger.com,1999:blog-8559314700259794131.post-598128253015777561
title: Synthesizer Extra's No.4: QUADRUPLE OFFSET BOARD for 3340 VCO.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/02/VCO%20Offset%20Board.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>Before I made Bi-Polar versions of the 3340VCO using 2 capacitors and an offset trimmer, I had the idea of using offset voltage on all outputs with an extra stripboard. In this article I explain how that would work. You can use this as a stand alone module of course and use panel potmeters instead of trimmers to set the offset voltage. It's up to you :)</p><div style="text-align: left;">The one thing that always bothered me about the Digisound 80 VCO is that the outputs signals are unipolar. They're 0 to +10 Volt peak-to-peak and that is not very compatible with the rest of the builds on this website. Because this Digisound 80 VCO is the most popular project on this website, I thought I would design a little stripboard that gives you 4 offset options to turn all the signals of that VCO into more useful bi-polar signals at -5/+5Vpp.</div><div style="text-align: left;">There are more elegant ways of doing this perhaps but this project is meant more for people who are beginning in the DIY synth hobby and who are building the Digisound-80 VCO as their first VCO and they want bi-polar signals from that VCO. If you're one of those people you can build this project to solve that problem. It's a very easy to build and cheap project.</div><div style="text-align: left;">Btw, the Digisound 80.6 Lowpass filter works well with the Digisound VCO because it has a 1µF capacitor on the input that shaves off the offset voltage But I don't recommend capacitors on the VCO outputs because they can also act as filters.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">OPTIONS:</span></b></div><div style="text-align: left;">You don't have to build this module into the 3340 VCO (project 18) if you don't have room. You can put this stripboard behind a small panel with just 4 input sockets and 4 output sockets and attach that next to the VCO. That way you have a choise of either using the outputs straight from the VCO at 0 to +10V or to patch them through this offset board and get -5/+5V output signals. That way you can also use the offset module for other things like LFO's if you want to.&nbsp;</div><div style="text-align: left;">You can even 'normal' the VCO outputs to the socket-switch lugs of the offset input sockets and save yourself the trouble of having to use patch cables.</div><div style="text-align: left;">You can even add bi-polar LEDs on the outputs so you have a visual indication of the Voltage they output. As you see, if you want, you can really go mad with this project but I leave that up to you.&nbsp;</div><div style="text-align: left;">Anyway, we also have the <a href="https://www.eddybergman.com/2020/11/synthesizer-build-part-36-dual-voltage.html" target="_blank">Dual Voltage Processor</a> project to cover that functionality and it has extra options too so maybe it's better to keep this project simple.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I put in four offset stages eventhough three will be enough for the 3340 VCO so you can use the other for something else.&nbsp;&nbsp;</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">It's a very simple design. Just 4 dual opamps, in this case TL072's (but you can use other ones if you wish as long as the pinouts are the same) each with an offset trimmer that allows you to give a negative 5V offset to the signals coming from the VCO and so turn them into bi-polar signals.&nbsp; I choose to give every stage its own offset trimmer so you can set them all differently should you need to, but in principal you could feed all four opamps with the voltage coming from one trimmer and so have them all produce the same offset. That's simpler but not preferable I think so I went with four trimmers.</div><div style="text-align: left;">The schematic below shows two of the four offset circuits that are on the stripboard but they are all the same.</div><div style="text-align: left;">If the output voltages of the VCO waveshapes are 8.2V instead of 10V and you want to crank it up to produce 10Vpp (-5/+5V) waveforms then change the 100K feedback resistor over pins 6 and 7 to a 130K. That will give just enough gain to get the right output voltage.&nbsp;</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDYBDEqB88UT10D5VNr50hfuuC0Jf2gsjBJRoOCCyvU5Zk2T9VLsaLYparGUf7kUQuIduVHtPV27UNK-qeBsTabIP3CA6DYfwGVdWj76Ry4VDLewSbkSyVbq8Pstmj2FKOeHn7Ha0R0giyDbWTvKxbuCelygpViODwuN2tuXRLr13hobVJpBngBApFjne8/s2864/OFFSET%20CIRCUIT%20FOR%20OUTPUTS.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2480" data-original-width="2864" height="277" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDYBDEqB88UT10D5VNr50hfuuC0Jf2gsjBJRoOCCyvU5Zk2T9VLsaLYparGUf7kUQuIduVHtPV27UNK-qeBsTabIP3CA6DYfwGVdWj76Ry4VDLewSbkSyVbq8Pstmj2FKOeHn7Ha0R0giyDbWTvKxbuCelygpViODwuN2tuXRLr13hobVJpBngBApFjne8/s320/OFFSET%20CIRCUIT%20FOR%20OUTPUTS.jpg" width="320" /></a></div><div><br /></div><b><span style="color: red;">LAYOUT:</span></b><div>Below is the layout for this project.&nbsp;</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8mLbnIWeft44r5T7gqc6g_Ghunh_BXo_9tASv2AyGwUwrBmT3ABjxIoQoK_hIOBKRdipfbCv53pFQV92QdcND_cgZBkOOHl3EJP7Oqpqbd-BqFcLHaC1iNPS20uG3BKo2jvy9vOZvklPPkoIYR_q2WZxrSXrNHdYuJuxTqXW6hD2TluWauAyji3RsQncU/s6149/Expansion%20board%20for%20Digisound%2080%20VCO%20-%20layout.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3830" data-original-width="6149" height="199" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8mLbnIWeft44r5T7gqc6g_Ghunh_BXo_9tASv2AyGwUwrBmT3ABjxIoQoK_hIOBKRdipfbCv53pFQV92QdcND_cgZBkOOHl3EJP7Oqpqbd-BqFcLHaC1iNPS20uG3BKo2jvy9vOZvklPPkoIYR_q2WZxrSXrNHdYuJuxTqXW6hD2TluWauAyji3RsQncU/s320/Expansion%20board%20for%20Digisound%2080%20VCO%20-%20layout.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><span style="font-size: x-small;">(Layout has been updated on 9th of March 2024. Previous version had 2 little mistakes in it.)</span></div><br /><div>Below is the layout with just the cuts and wirebridges, seen from the component side. As ever, mark the cuts on the component side with a waterproof Sharpie. Then put a pin through the marked holes and mark them again on the copper side. Then cut the strips with a sharp hand held 6 or 7mm drill bit.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8GnpF4AJmuo8a9IQ8Hs9mYyUxtVfdJOPjym_KAWGKF0PcorlwQxDFFy_m9fSfgOfsLqJz6rTS7cfasI09x-chBFfdP1aJ6g6vf7rUT9o4z6DxDuocunGqjwfT4zx_pfgqj8zKsgK31BgfrWtvnLkVCVL9Rm4AI0I0CSweda-k-6qONPCS8IfrIpil2rO6/s4677/Expansion%20board%20for%20Digisound%2080%20VCO%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3219" data-original-width="4677" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8GnpF4AJmuo8a9IQ8Hs9mYyUxtVfdJOPjym_KAWGKF0PcorlwQxDFFy_m9fSfgOfsLqJz6rTS7cfasI09x-chBFfdP1aJ6g6vf7rUT9o4z6DxDuocunGqjwfT4zx_pfgqj8zKsgK31BgfrWtvnLkVCVL9Rm4AI0I0CSweda-k-6qONPCS8IfrIpil2rO6/s320/Expansion%20board%20for%20Digisound%2080%20VCO%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><div><br /></div><div>If you decide to build this into the Digisound VCO module, then it may be better to do away with the eurorack connector and simply use wire connections for the power. That way you can make the stripboard more compact too. The lower 4 copper strips are not used either so you can cut those off too or use the space to house the standoffs to connect the stripboard to the rest of the VCO.</div><div>I did not actually build this project myself but I know it should absolutely work the way it's presented here so that should not be a problem. I built so many offset circuits while I've been doing this hobby that I can dream them.</div><div><br /></div><div>Here's the Bill of Materials for this project. Also order four 100nF ceramic bypass capacitors. I forgot to put them in this list.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-2AuOBvRUs7xm2C7yVUMoTXglaSALRYg-kdpy31uhD8MzmVFOvRSFgswTTqS7EDj_BdL-gjMhfgcCTRBScw9K9vs5dQ9OQFHdCGjehZlBVo9o3kkvL3p-vRFhnnd0IhQuz9G_pWYufhO6mFy7pSpI9bNDCPwHXmtLM10C0WpjbNK3filxZP_MfrMbYVbu/s863/Expansion%20Board%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="124" data-original-width="863" height="46" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-2AuOBvRUs7xm2C7yVUMoTXglaSALRYg-kdpy31uhD8MzmVFOvRSFgswTTqS7EDj_BdL-gjMhfgcCTRBScw9K9vs5dQ9OQFHdCGjehZlBVo9o3kkvL3p-vRFhnnd0IhQuz9G_pWYufhO6mFy7pSpI9bNDCPwHXmtLM10C0WpjbNK3filxZP_MfrMbYVbu/s320/Expansion%20Board%20BOM.JPG" width="320" /></a></div><br /><div><b><span style="color: red;">TUNING THE CIRCUIT:</span></b></div><div>You need an oscilloscope to set the offset trimmers to the right value. <span style="color: #fff2cc;">Make sure you set the oscilloscope to DC when measuring otherwise the scope won't show offset voltage.</span> Remember offset voltage is a DC voltage.</div><div>Connect the signal(s) from the VCO output to the input(s) of this stripboard and then connect the scope probe to the output(s) and set the offset voltage so that the signal displays the same amplitude on the positive side as the negative side of the zero Volt line. In other words, set it so the zero Volt line cuts nicely through the middle of the signal. That's it.&nbsp;</div><div><br /></div><div>Okay, that's all I have to say on this little extra project. I thought it might come in handy because the Digisound-80 VCO is really a very cool VCO and now you can make the signals more compatible with the rest of the projects on this website.</div><div>I hope it comes in handy.</div><div><br /></div><div>If you have any questions about this project feel free to comment below or on the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group</a> for this website.<br /><div style="text-align: left;"><br /></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-8295444102597313720
title: Synthesizer Build part 55: CROSSFADER with VACTROL CV CONTROL.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/03/xfade%20for%20DIY%20modular.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>This circuit lets you fade between two inputs manually or with a Control Voltage by means of two Vactrols. Project fit for Eurorack or Kosmo modulars.&nbsp;</p><div style="text-align: left;">This was an other project by request and since I haven't built anything like it yet, it seemed like an ideal project for the website, so I decided to look for a good crossfader schematic.&nbsp;<br />I came across a schematic from "sfcs.neocities.org ©Astro / SYNTHFOX 2020" on which it said 'okay to redocument when properly credited', so I hope this is okay.</div><div style="text-align: left;">I built this project for Eurorack but of course it can just as easily be built for a Kosmo sized synthesizer. In fact with a Kosmo module you have more space to put in more stages so that would be even better.</div><div style="text-align: left;"><span style="color: #fcff01;">This project works on both -12/+12V and on -15/+15V without needing any changes.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's the schematic I used:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5zkicYS9iotcdtpLVvkeV3QBffZtekjZSb3rEylCbjg_lf6i0Yw1QDer6JHNbnDbmAupBR1TsZP7Uaqo40p6m-th8DVqRiHtwD6OnT1VykWZH8f6VRvifDae3TXa6VddFjVEEpucfYIYemLYOpekMPzvdlbxlSWXLIp7N7w50jMW-ERLbSgJ8CPlWTFce/s1544/Crossfader%20Vactrol%20Based%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="750" data-original-width="1544" height="155" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5zkicYS9iotcdtpLVvkeV3QBffZtekjZSb3rEylCbjg_lf6i0Yw1QDer6JHNbnDbmAupBR1TsZP7Uaqo40p6m-th8DVqRiHtwD6OnT1VykWZH8f6VRvifDae3TXa6VddFjVEEpucfYIYemLYOpekMPzvdlbxlSWXLIp7N7w50jMW-ERLbSgJ8CPlWTFce/s320/Crossfader%20Vactrol%20Based%20schematic.JPG" width="320" /></a></div><br /><div style="text-align: left;"><b><span style="color: red;">HOW IT WORKS:</span></b></div><div style="text-align: left;">It's a very simple circuit. You have a DC voltage that can swing between the voltagerails coming into the inverting input of an opamp by means of the 'Init' potmeter (Initial Voltage) and a second connection in the shape of a Control Voltage input with a level control, summed to the same input on the opamp. The output of this opamp controls the lighting up of the LEDs in the Vactrols. One Vactrol does the negative phase and one does the positive phase, or one does input A and the other input B. Whichever you prefer.&nbsp;</div><div style="text-align: left;">The LDR's (Light Dependent Resistors) of the Vactrols are each connected to one input source and the other sides are connected together and go into the second opamp which is simply an output buffer. That's all there is to it.</div><div style="text-align: left;">The CV input comes in via a lower resistance than the Initial Voltage, 22K instead of 100k. This will, in combination with the 100K feedback resistor R4, give the CV input an extra gain. We can calculate that gain with the formula: Gain = (-Rfeedback / Rin) which is -100/22=-4.45 The minus symbol simply means that the output voltage is inverted.&nbsp;</div><div style="text-align: left;">This is done (I think) to give lower control voltages enough effect to influence the vactrols because a CV voltage can never be as high as the Initial Voltage which covers the full powerrails potential. So if your CV input is not effective enough you can try lowering R2 and so get even more gain, but don't overdo it. Measure first before you start altering things. Make sure this change is actually needed. (I left it as it was myself).</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I built one Crossfader stage as seen on the schematic but it would be easy enough to build a few of these so you can mix together more inputs. The circuit, as you can see, only has a few parts so it doesn't take up much room.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">With the Init potmeter (Initial Voltage) you can manually fade between the two inputs. This works as long as there's no CV voltage present. When you input a CV voltage that will then take over control of the crossfading the higher you set the CV Level and you can steer the output signal more to one or the other input with the Initial Voltage control potmeter.</div><div style="text-align: left;">I made the Vactrols myself, in fact I used Vactrols I had already made for the LowPass Gate project, so I don't know exactly which LDR's I used to make them with but I used red 5mm LEDs in them. It is preferable to use red LEDs because they have the lowest voltage drop (about 1,5V) but with the extra gain the CV input gets I don't think this is very important. LDR's do react well to red light. The LDR's I used have a resistance of about 300Ω when the Vactrol is switched fully on. I think it is best to use quick reacting LDRs in the Vactrols so it can handle a wide range of LFO frequencies on the CV input.</div><div style="text-align: left;">The test results I got after finishing building this project showed that, when using the CV input I still got some bleed through of one signal onto another. In other words the separation of inputs A and B was not perfect when the CV voltage was on full positive or negative voltage. With just the manual control (Initial Voltage pot) I did get a good separation between the signals when the potmeter was fully clockwise or counter-clockwise. Of course the total voltage of the CV input could be the problem here. If it is not as high as the voltage produced by the Init. potmeter then it won't have as much influence. That is why the CV stage has extra gain on it to boost the signal.</div><div style="text-align: left;"><span style="color: #fff2cc;">So please don't expect perfection from this analog Vactrol design. It's old school and that's what I like about it.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Here are the layouts I made for this project. As ever they are verified. I used them for my build.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhImVjJ9nqiJzWy1-AhpgNeaFtqlcSYRyUHZD4NuQI-baoh84tnseXg8uPR7-YRksz75lLSEFclUDwg0L9H-2twuKvZHpKzeGJLXAF4AkPEIv7-ZYLrA2gfGFeKnmAimOjrebkn67Ww6R1-YBB86AKq_m0lJI0Udq4yt9-1b7yHoSVXbAvdBfWSCsvIZKK-/s5948/Crossfader%20Vactrol%20Based%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5524" data-original-width="5948" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhImVjJ9nqiJzWy1-AhpgNeaFtqlcSYRyUHZD4NuQI-baoh84tnseXg8uPR7-YRksz75lLSEFclUDwg0L9H-2twuKvZHpKzeGJLXAF4AkPEIv7-ZYLrA2gfGFeKnmAimOjrebkn67Ww6R1-YBB86AKq_m0lJI0Udq4yt9-1b7yHoSVXbAvdBfWSCsvIZKK-/s320/Crossfader%20Vactrol%20Based%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Stripboard only:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijPCgcqY0IYBPb68neW6ax5BEnAtG-n8-MmpgDRvgAC1br7KtTISJpH2EeZy7kTgdhrwEtCxQUiz0LkH3Phb7V2UZCLzUvJxetsdxJS49B5jkG7xaF6kQN_mK3qYNHnsH0Y3bittmQFnNi5yC92ZcmuAuBr9jxth8Hzkym8ePYPPrxUojrh1ye8fz97zuX/s2857/Crossfader%20Vactrol%20Based%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2857" data-original-width="2408" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijPCgcqY0IYBPb68neW6ax5BEnAtG-n8-MmpgDRvgAC1br7KtTISJpH2EeZy7kTgdhrwEtCxQUiz0LkH3Phb7V2UZCLzUvJxetsdxJS49B5jkG7xaF6kQN_mK3qYNHnsH0Y3bittmQFnNi5yC92ZcmuAuBr9jxth8Hzkym8ePYPPrxUojrh1ye8fz97zuX/s320/Crossfader%20Vactrol%20Based%20-%20Stripboard%20only.jpg" width="270" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Cuts and wirebridges. As ever, mark the cuts with a Sharpie. Stick a pin through the marked holes and mark them again on the copper side. Then cut the strips where marked with a sharp hand held 6 or 7mm drill bit.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7mp9jMCEmTdncrXWXi_iXjUNmT-BM0BT3TF7jMMXZTHE_s6eK_SByKoXwJFoEZWTOQJVB-ddsziKu2eiFdFKTppbl6REFyjUiWnxh75rELDB7vWiknJqM1BLO358Bo-Z5WxOpj4CEZqqQdkM69NPmiaIICRCvX9ypWJlOMwybnUp4Rn5BhTz_wINyLCco/s2997/Crossfader%20Vactrol%20Based%20cuts%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2997" data-original-width="2486" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7mp9jMCEmTdncrXWXi_iXjUNmT-BM0BT3TF7jMMXZTHE_s6eK_SByKoXwJFoEZWTOQJVB-ddsziKu2eiFdFKTppbl6REFyjUiWnxh75rELDB7vWiknJqM1BLO358Bo-Z5WxOpj4CEZqqQdkM69NPmiaIICRCvX9ypWJlOMwybnUp4Rn5BhTz_wINyLCco/s320/Crossfader%20Vactrol%20Based%20cuts%20wirebridges.jpg" width="265" /></a></div><br /><div>Here's the Bill of Materials. If you make your own Vactrols then refer back to the <a href="https://www.eddybergman.com/2020/10/synthesizer-build-part-35-resonant.html" target="_blank">Lopass Gate project</a> to get more info on the LDRs I used there. There's a complete paragraph discussing the Vactrols in that article. I did not include any bypass caps in the BOM so if you want them, order two 100nF ceramic caps and solder them from positive to ground and from ground to negative power at the top of the stripboard.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhY6xoulOj49jzaVXcMDumJ81vO5NX0urGxQPcSszfhZyWag3S1zuvu6pKBZzD5xefKvDT5rXO8sI3ZlpZi22q2WiIW7fUoPEw6h_R8VLwW1C-v_SJH_u1N0IO5_PPepPd58B3iV98rvmeHzunfzdkuSmUdPYEkbStNecZRNbeO5Rt7IpLnZRdVU9eetaqt/s720/Crossfader%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="258" data-original-width="720" height="115" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhY6xoulOj49jzaVXcMDumJ81vO5NX0urGxQPcSszfhZyWag3S1zuvu6pKBZzD5xefKvDT5rXO8sI3ZlpZi22q2WiIW7fUoPEw6h_R8VLwW1C-v_SJH_u1N0IO5_PPepPd58B3iV98rvmeHzunfzdkuSmUdPYEkbStNecZRNbeO5Rt7IpLnZRdVU9eetaqt/s320/Crossfader%20BOM.JPG" width="320" /></a></div><br /><div>Here are some pictures of the finished module. Mine is 6hp wide (3CM) and about 5,5CM deep which is a lot but it will fit in a Nifty Case, no problem.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMaK7gDVwIXnQ0vlRGtxfmMQoHbU8DxA4uftcoSx1oNVW0k3kGvv_8kY9Gm5ys5vbHIA_qLyMijXXcQ2MXyVhK9lpyh_O9k-DjVhi28uarGpINbAkJKU31mbsS3GmMTZDB3L-Auy5RcEWwSIzsZ_5zp13mlBMEFkQMWQSfLzSAyjWH_1exZwK22Bxhs2-4/s4000/20240311_200432.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMaK7gDVwIXnQ0vlRGtxfmMQoHbU8DxA4uftcoSx1oNVW0k3kGvv_8kY9Gm5ys5vbHIA_qLyMijXXcQ2MXyVhK9lpyh_O9k-DjVhi28uarGpINbAkJKU31mbsS3GmMTZDB3L-Auy5RcEWwSIzsZ_5zp13mlBMEFkQMWQSfLzSAyjWH_1exZwK22Bxhs2-4/s320/20240311_200432.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTQwOHEwFTsMXE849j01nxgmEG_dqn-aIdn0LbgaHnvVZ0E8Sb_Yd2obZ41ztgejA85m_zb5dzsymYyveX6Z85O8Q5IdzzFXoYTazOVDMHVe5CfGZtDHHkXvI-XEoJA2lce1Z4UWGieAiJnwd_Na_m2Eb_heWRzyVZUOjI0oGHOeidJQm1nlIuui6RYKl4/s4000/20240311_200443.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTQwOHEwFTsMXE849j01nxgmEG_dqn-aIdn0LbgaHnvVZ0E8Sb_Yd2obZ41ztgejA85m_zb5dzsymYyveX6Z85O8Q5IdzzFXoYTazOVDMHVe5CfGZtDHHkXvI-XEoJA2lce1Z4UWGieAiJnwd_Na_m2Eb_heWRzyVZUOjI0oGHOeidJQm1nlIuui6RYKl4/s320/20240311_200443.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">The two striped components on the top near the power header are just 100nF bypass caps. You can include them of leave them out. They're not really necessary and I left them out of the layouts and bill of materials.&nbsp;</div><div class="separator" style="clear: both; text-align: left;">In front of the vactrol you can see a little pin header. There's also one on the other side that you can't see. I soldered those in for test purposes. I could connect my multimeter probes to it to measure the resistance of the LDRs in the vactrols.</div><br /><div><b><span style="color: red;">SCOPE IMAGES:</span></b></div><div>Here are some screenshots from the oscilloscope. In the three images below the yellow line is the output signal, the blue is input A and the purple is input B.</div><div>The first image represents the crossfader with the Initial Voltage potmeter fully counter-clockwise so only the squarewave is let through to the output. There is no CV input present in any of these screenshots.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpUVBKckcMuZwSdFdd0ahYLlbeM_DRp5GcOb4oyTJ0RxDREDnmBePFwCVTma71h53s5CVeyTYgvotV3AEzDH9gq5HoBCROvOeUMD6LmPSVn6EGp0czG72Q60Bad8pFCHgQOkUFL0cjTZDq8Fxwk7uqYJ2AJvAB5Ebc4-tkEhkzlyj7xccG8Sj-qCY3CIAQ/s800/Square.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpUVBKckcMuZwSdFdd0ahYLlbeM_DRp5GcOb4oyTJ0RxDREDnmBePFwCVTma71h53s5CVeyTYgvotV3AEzDH9gq5HoBCROvOeUMD6LmPSVn6EGp0czG72Q60Bad8pFCHgQOkUFL0cjTZDq8Fxwk7uqYJ2AJvAB5Ebc4-tkEhkzlyj7xccG8Sj-qCY3CIAQ/s320/Square.jpg" width="320" /></a></div><div><br /></div>In the second image the Init potmeter is in the middle position and we get a mix of both inputs A and B.<div>As you can see here with the blue and purple traces some of the signal is fed back on to the input signals, changing their character a bit but this is easily explained. When both vactrols are fully active the output and both inputs are separated from eachother by only about 600Ω, the series resistance of the vactrol LDRs, so it's obvious some of the input A signal will find its way to input B and vice versa. This is not a problem however and it can not damage your VCO's. Exactly the same happens when you mix signals with a passive multiple for instance, so nothing to worry about.<br /><div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibjLptjALldYJdez9od2MMK_Gmcppp3eXAxAQKVxUG3kkVQzwcwFLuv7F6MewxF_s1CyE7DNoqv2FgwJVMmuTO6z4Bs9_TUTJEwA7WIig6hZn7Bq4EjYqxyhuX20q5HUJBgDU2dmA2WgNwPdLRp_5nfbsEx8xtYa2obWvlFQqO1gW3twhQuY6pDKTh48z5/s800/Middle.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibjLptjALldYJdez9od2MMK_Gmcppp3eXAxAQKVxUG3kkVQzwcwFLuv7F6MewxF_s1CyE7DNoqv2FgwJVMmuTO6z4Bs9_TUTJEwA7WIig6hZn7Bq4EjYqxyhuX20q5HUJBgDU2dmA2WgNwPdLRp_5nfbsEx8xtYa2obWvlFQqO1gW3twhQuY6pDKTh48z5/s320/Middle.jpg" width="320" /></a></div><div><br /></div><div>And in this third image the Init. potmeter is set fully clockwise so only the Triangle wave is let through.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXIMlJUpjizYd6oeFyi2-2OmKhnsDE4RmheX_CFTBaMPPlZYvT-eY3fMxzKS0VFvW3wSBNCRFY7SwY3di3Z1Dwah-Uu-02sIsg8ok7nDF7W1zB60j5H7YJXGvTyNLikU-p726r19HUz5Pc4f0l3Ok6akgnKdGE_xSIkbOew4LrNZqIGRDH6NVIINtam1cl/s800/Triangle.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXIMlJUpjizYd6oeFyi2-2OmKhnsDE4RmheX_CFTBaMPPlZYvT-eY3fMxzKS0VFvW3wSBNCRFY7SwY3di3Z1Dwah-Uu-02sIsg8ok7nDF7W1zB60j5H7YJXGvTyNLikU-p726r19HUz5Pc4f0l3Ok6akgnKdGE_xSIkbOew4LrNZqIGRDH6NVIINtam1cl/s320/Triangle.jpg" width="320" /></a></div><br /><div>If you connect a sinewave LFO to the CV input and turn the level up, then the result will be a cycling through these three stages. By turning the Initial Voltage potmeter away from the middle position you can emphasize&nbsp;one of the input signals.</div><div><span style="color: #fcff01;"><span>The signal that is connected to the CV input needs to be a bi-polar signal</span>, </span>so a signal that has a negative and a positive voltage phase otherwise it will only fade one of the inputs. If you want to use a uni-polar signal, you could try using a capacitor on the CV input socket to turn a uni-polar signal into a bi-polar signal but I haven't tried that myself.</div><div><br /></div><div>Here is a little test video I made while I was testing the circuit just after finishing it. You hear me discussing a CV leakage problem, that when the CV Level is fully closed it still had some influence, but that turned out to be a grounding issue, as I thought it must be, and once I put the stripboard behind an aluminium faceplate and wired everything up that issue was no longer there. So problem solved.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dz4OiM-CqAY_KVe1Sx7jdKNHmJvxTWeUJIFwkNTjxEILn8xYjBnZ4rkq5X8Qd7uaZzOVcOip505PZYHUnE1Fg' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div>Okay, that's it for this project. A simple one just like the previous last few projects because I didn't have time to do really big projects in the last few months. However I am working on some new and bigger projects so watch this space :)</div><div><br /></div><div>If you have any questions about this project please comment below or post your question in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group</a> for this website.</div><div><div><div class="separator" style="clear: both; text-align: center;"><br /></div></div></div></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-1336870909086123087
title: Synthesizer Build part-56: VCF-1 STATE VARIABLE FILTER by THOMAS HENRY.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/04/THVCF1statevariablefilter.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">&nbsp;A very easy to build and awesome sounding state variable filter by Thomas Henry. For Eurorack or Kosmo systems.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">There are PCBs available for this VCF. See&nbsp;<a href="https://www.eddybergman.com/p/pcb-service.html" target="_blank">'PCB Service'</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">I have covered many different types of filters on my website but I had not yet built a State Variable filter. What does that even mean I hear you ask. Well state variable means that it can simultaneously provide two or more types of filtering. In this case the filter has Lowpass, Highpass and Bandpass outputs and rather than having to switch the filter into these different modes, you have them available together, so each filtertype has its own output.</div><div style="text-align: left;">I found this particular schematic on "<a href="https://www.birthofasynth.com/Thomas_Henry/Pages/VCF-1.html" target="_blank">Birthofasynth.com</a>", a website that has all of Thomas Henry's projects on it.</div><div style="text-align: left;">In the article about this filter he calls it a 'barebones' filter. Very much taken straight from the CA3080 datasheet. That may be so but it's still a great sounding filter. The way it sounds reminded me of the Steiner-Parker filter. However the resonance is different in how it reacts to envelope pulses.&nbsp;</div><div style="text-align: left;">It's a really old school filter with a 12dB/Oct. cutoff slope (2 pole filter) and it sounds like a 70's synthesizer filter should sound. It's pure sounding, phat in the low end (especially using squarewaves in Lowpass mode) with a beautiful but little bit agressive resonance. I own a Behringer Odyssey and that synth has a choise of three filters and one of them is a 12dB/Oct. filter and that is my favourite type of VCF. I always have the Odyssey set to the two pole filter. Anyway I urge you to read the article I linked to above if you want to know more about what TH said about this filter and its development.</div><div style="text-align: left;"><span style="color: #fcff01;">THIS FILTER WILL RUN FINE ON BOTH A DUAL 12V OR A DUAL 15V POWERSUPPLY!</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">Below is the schematic I used for this filter. It says the filter is to be used with a dual 15V powersupply but I did all my testing running it on a dual 12V powersupply because many of you will be building this for Eurorack and it works just fine. I also used a Eurorack friendly size of stripboard which is 24 by 41 holes. That will fit behind a Eurorack panel.</div><div style="text-align: left;">As you can see the filter uses two OTA chips, the AS3080. These are the modern version of the original CA3080 chips and I believe these are less noisy than the originals too but they have that original sound. I got mine from <a href="https://electricdruid.net/product/as3080e-ota/" target="_blank">Electric Druid</a>, They are also available at <a href="http://thonk.co.uk/shop/alfa-as3080e/" target="_blank">Thonk</a> and other online retailers.&nbsp;</div><div style="text-align: left;"><br /></div><div style="text-align: left;">The LM13700 OTA chip also has two CA3080 chips inside and it should be possible to use it in this circuit but then you'd have to design your own layout because that is a DIP16 IC.&nbsp;</div><div style="text-align: left;">I've had feedback from people using the 13700 that they get significant offset voltages on the outputs. For more on this please check out the comments below for comments by IDYLLM. He analysed this and came up with solutions.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">For this particular project you'll need the AS3080 chips so please don't compromise on this and just order some AS3080's. They're easy to find and not that expensive. You only need two.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixGQGIRcx83Db1tN22xzIDJm_3q1cGF5fZUjIPxZCJX7kH3s9hK4ik8TCZdUBEyD2ykDoOJ9vaW1OOSxUsYhTS8GEMM67pt5OqpnjMEXWdkDdReHEgBFdJ70_SL6LhwiTO4DJup8kMnAhJ2p8rneb868AKkIA27KpWTzgLSZhyphenhyphenp0Wd3dbVxyw1eA6dkyMH/s1677/VCF-1%20full%20schematic%20v2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="834" data-original-width="1677" height="159" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixGQGIRcx83Db1tN22xzIDJm_3q1cGF5fZUjIPxZCJX7kH3s9hK4ik8TCZdUBEyD2ykDoOJ9vaW1OOSxUsYhTS8GEMM67pt5OqpnjMEXWdkDdReHEgBFdJ70_SL6LhwiTO4DJup8kMnAhJ2p8rneb868AKkIA27KpWTzgLSZhyphenhyphenp0Wd3dbVxyw1eA6dkyMH/s320/VCF-1%20full%20schematic%20v2.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><span style="font-size: small;">The numbering of the opamp pins has been changed to fit the layouts below, because I used the opamps in a different order to the original schematic.</span></div><div><br /></div><div>A reader of this blog (Syboxez) made a great Falstad simulation of this filter which you can watch by clicking on this link:&nbsp;<a href="https://tinyurl.com/ymtmstrb" target="_blank">-- VCF-1 SIM --</a></div><div><br /></div><div>The schematic shows a two transistor exponential converter with a PTC as temperature compensation. which we already know from the Thomas Henry 555-VCO. The temperature compensation is only useful if you intend to use the self oscillation of the filter as an extra oscillator. I never used a filter in this way and I can't imagine any of you will ever use the filter for that purpose so you can leave out the PTC and just use a 2K resistor. That's what I did eventhough I have these PTC's in my stock. In fact Thomas Henry himself used a 2K resistor as he mentions in the article linked above.</div><div>You do have to match the two PNP transistors though. I matched them using my Ian Fritz method matcher that I built on PCB but matching on Hfe with a multimeter should be good enough.</div><div>You might use the filter in full self resonance mode if you're looking for a special sound effect. I tested it and it will track with the keyboard because it has a Volt per Octave input. I have not tested how accurate the tracking is but I do think you can make it track over a few octaves if you want. Beware that the self oscillation is about twice as loud as the normal audio you get from this filter!!</div><div>You can leave out the Frequency Fine Tune potmeter too because that's only there to tune the self resonance for tracking. As a Cut-Off Frequency potmeter it is pretty much useless. One thing you can do is change the 3M3 resistor to a 100K and add a socket to that potmeter so it turns into an extra CV input with level control. Wire it up like the Envelope input. That's what I did myself.&nbsp;</div><div>I find two CV inputs a necessity for a filter. There's a little layout further down showing how to do this.</div><div><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Below are the layouts I made for this build. As always they are verified. I used them to build my filter. I was very thorough with checking this stripboard layout for faults before I printed it out and used it to start building my filter. I'm glad I checked it over a few times because I did manage to catch some mistakes in the design fase which saved me some hours troubleshooting I think.</div><div style="text-align: left;">Anyway the build went fine and apart from one transistor being faulty which needed changing out the filter worked straightaway.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's the <b><span style="color: red;">wiring diagram</span></b>:</div><div style="text-align: left;"><span style="color: #fff2cc;">All potmeters are seen from the BACK SIDE!</span></div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCBMOmlmSsl6QEEMUuVCnJO2kp5_driDe786AZGcVJ_8LRAUw2SM7GJFuPtoRgU0I5C3b_MvOh61_yGKIMCWWbt_U9Hy0gZdfzkcHCYuA3n61p9FgNwb7rbHkCtXtqMJHR_f7fcxtIKxENTVo2lmep_9ut3pdqs0RgSOxEEOD3Pa9D_YTETOfkWguLWJeO/s10365/VCF-1%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4413" data-original-width="10365" height="136" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCBMOmlmSsl6QEEMUuVCnJO2kp5_driDe786AZGcVJ_8LRAUw2SM7GJFuPtoRgU0I5C3b_MvOh61_yGKIMCWWbt_U9Hy0gZdfzkcHCYuA3n61p9FgNwb7rbHkCtXtqMJHR_f7fcxtIKxENTVo2lmep_9ut3pdqs0RgSOxEEOD3Pa9D_YTETOfkWguLWJeO/s320/VCF-1%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>The Cutoff Frequency potmeter is wired up in such a way that the filter opens up when you turn it clockwise. The Resonance potmeter is wired up so that it gives more resonance when you turn it clockwise going into self oscillation when turned fully clockwise. It looks asif the wiring of the Resonance potmeter is the wrong way around but that's not the case. Resonance increases when the wiper moves clockwise towards the connection to ground. Resonance potmeters are usually wired up like this.</div><div><br /></div><div><span style="color: red;"><b>EXTRA CV INPUT:</b></span></div><div><span>As I mentioned earlier, the Frequency Fine Control is meant to tune the self oscillation of the filter so that it tracks with the keyboard. In itself it has very little influence on the CutOff Frequency so if you intend to use this filter just as a VCF and the tracking accuracy of the self oscillation isn't important to you then leave out the fine control potmeter. It will save some space on the faceplate too. I myself left out the Fine control potmeter too. I changed the 3M3 resistor for a 100K one and connected a second CV input to that point, complete with level control potmeter like the envelope input. Here's a detail of what that looks like:</span></div><div><span style="color: #fff2cc;"><br /></span></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcIIxU_tTL1BrcCYQVvX5KQJtzk2I_zJUBOGBS0K69ShG3K5E5qz7lZHb220IcWsPLfG-nHMd70mtvuPdC2yWd3E-gfh5I24u9GW6yehu0e9IHkMo6kd_PxBIUmuUDBbawDKOseHcwrPoEs5ieOAKFQyJtW_q_wOY6aZZyHC2UVOf8Bdx8fyMRb89_12_4/s4049/VCF-1%20w%20extra%20CV%20IN%20detail.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2802" data-original-width="4049" height="221" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcIIxU_tTL1BrcCYQVvX5KQJtzk2I_zJUBOGBS0K69ShG3K5E5qz7lZHb220IcWsPLfG-nHMd70mtvuPdC2yWd3E-gfh5I24u9GW6yehu0e9IHkMo6kd_PxBIUmuUDBbawDKOseHcwrPoEs5ieOAKFQyJtW_q_wOY6aZZyHC2UVOf8Bdx8fyMRb89_12_4/s320/VCF-1%20w%20extra%20CV%20IN%20detail.jpg" width="320" /></a></div><br /></div><div>As you can see it's very simple. I would really advise you to add this second CV input. Filters really need two CV inputs the get the most out of them. One for the Envelope signal and one for special effects like an LFO.</div><div><br /></div><div><span style="color: red;"><b>Stripboard only view:</b></span></div>Below is the stripboard only view. A little tip, when soldering in the trimmer potmeters put the wipers in the middle position. That way you won't have to do much tuning when you're testing the filter.&nbsp;<div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDiQDGZBpT_ZBLErdc6fbLvV-19xxBI3LoJBBum-cuFLjP-NcxAU7FZPW3wlsIhnR946i1hllobgz02e-H20pKFLWu0AuB6LnE1phC_PoGJP8FWs6bScPvCTgBPX-QexXhBYiyiHcslEKzq-7Lo7LwkpDBbmLkAIXI1Hle93XhipUvVXs2lca62NvxKPU8/s4684/02%20VCF-1%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2845" data-original-width="4684" height="194" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDiQDGZBpT_ZBLErdc6fbLvV-19xxBI3LoJBBum-cuFLjP-NcxAU7FZPW3wlsIhnR946i1hllobgz02e-H20pKFLWu0AuB6LnE1phC_PoGJP8FWs6bScPvCTgBPX-QexXhBYiyiHcslEKzq-7Lo7LwkpDBbmLkAIXI1Hle93XhipUvVXs2lca62NvxKPU8/s320/02%20VCF-1%20stripboard%20only.jpg" width="320" /></a></div><br /><div><b><span style="color: red;">Cuts and wirebridges:</span></b></div><div>Here's an overview of the cuts and wirebridges. Start soldering these in first before you solder in any components. There are 35 wirebridges to solder in. Make sure you're very very accurate here. It's easy to make a mistake and one wirebridge in the wrong position and the filter won't work.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjy1WIyj_ZdEeZCJ7dHCQ6g5J0sB066k3AXW7Hs78ucpoJbkbe7xIadiMg2fdMoG3-ay8OxBTHJbRfc2QxQcI6S1DQH1p1oDpFdS0CsiZlT88JYHCHbmB2qu_Idqp6sb-LX2HbtF-LF6npjcf5MWOGnwJRZD-2KtoATQ8GVoZHwsM6wDR96-e1oOtlsuVLd/s4733/03%20VCF-1%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3135" data-original-width="4733" height="212" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjy1WIyj_ZdEeZCJ7dHCQ6g5J0sB066k3AXW7Hs78ucpoJbkbe7xIadiMg2fdMoG3-ay8OxBTHJbRfc2QxQcI6S1DQH1p1oDpFdS0CsiZlT88JYHCHbmB2qu_Idqp6sb-LX2HbtF-LF6npjcf5MWOGnwJRZD-2KtoATQ8GVoZHwsM6wDR96-e1oOtlsuVLd/s320/03%20VCF-1%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><br /><div><b><span style="color: red;">Cuts only:</span></b></div><div>And finally the cuts only as seen from the component side. As always, mark the cuts on the component side first with a waterproof Sharpie or Edding 3000 and then stick a pin through the marked holes and mark them again on the copper side. Then you can cut the strips at the marked places with a sharp hand held 6 or 7mm drill bit. This way you have the least chance of making mistakes.</div><div><span style="color: #fff2cc;">Once again you need to be very accurate here because the component placement leaves no room for errors.</span></div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNQS_3tXNKJZCqJdFdole9H1D0vzCcmoNkA5W6S-w-7eufF02_RtJlJjXexwR_VwtjYLdFOh0AnbqyzGrzC9g0xrqVllmBtVZ3hKF793O2Y9s0dJkPQefft4Yx_Cf3UgtD3maLvtJD9JYJ3Mu9aU_XLqdRbpIRrkZqReAnsj_S6cSUZHvEdpiyoZeu3YOW/s4733/04%20VCF-1%20cuts%20only%20component%20side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3080" data-original-width="4733" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNQS_3tXNKJZCqJdFdole9H1D0vzCcmoNkA5W6S-w-7eufF02_RtJlJjXexwR_VwtjYLdFOh0AnbqyzGrzC9g0xrqVllmBtVZ3hKF793O2Y9s0dJkPQefft4Yx_Cf3UgtD3maLvtJD9JYJ3Mu9aU_XLqdRbpIRrkZqReAnsj_S6cSUZHvEdpiyoZeu3YOW/s320/04%20VCF-1%20cuts%20only%20component%20side.jpg" width="320" /></a></div><br /><div>And here's the <b><span style="color: red;">Bill Of Materials</span></b>:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHp8-rbUX-wB-3VzaAVbb-JdnN6sZOMhKXIqXK7Ob0oBK0yRWCHRCSNYrmp6-Dq3dsAWeksn4UFub36fVd2PgsiL_Vg43kMR4FO3pVaWcWfNKcKriNpjCkuAZuQBGhcHJMu-rXSU5CZkKYRSzvcQpcO8KA8lw4pas0Jzghp2UyG9QQGI-tnlYawfnX3gP7/s1340/VCF-1%20Bill%20Of%20Materials.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="516" data-original-width="1340" height="123" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHp8-rbUX-wB-3VzaAVbb-JdnN6sZOMhKXIqXK7Ob0oBK0yRWCHRCSNYrmp6-Dq3dsAWeksn4UFub36fVd2PgsiL_Vg43kMR4FO3pVaWcWfNKcKriNpjCkuAZuQBGhcHJMu-rXSU5CZkKYRSzvcQpcO8KA8lw4pas0Jzghp2UyG9QQGI-tnlYawfnX3gP7/s320/VCF-1%20Bill%20Of%20Materials.JPG" width="320" /></a></div><div><br /></div><div>If you're going to build this module for Eurorack then I urge you to order miniature potmeters. You're going to need all the space you can get. There are 5 potmeters to accomodate and 7 sockets.</div><div>These are the pots I mean:</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJcMrPgnaR8hBbvRHrzBJB8S_r-BwSU7WkejTfRLJQ1Ao7_jXQg_Yws1NGECV7Be-JlvDBsgfr8-LYuHSnLWukLXsY0MGlsNU7kuczrCwlkB9qpKXVquqEIDkhQXK71nPm4FpL0zQW46OrM-nYHQUU0R4uXVk3b0o7Tm2GrWMR-tyH40Q_j4tFV8D8-m75/s245/Miniature%20pots.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="245" data-original-width="212" height="245" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJcMrPgnaR8hBbvRHrzBJB8S_r-BwSU7WkejTfRLJQ1Ao7_jXQg_Yws1NGECV7Be-JlvDBsgfr8-LYuHSnLWukLXsY0MGlsNU7kuczrCwlkB9qpKXVquqEIDkhQXK71nPm4FpL0zQW46OrM-nYHQUU0R4uXVk3b0o7Tm2GrWMR-tyH40Q_j4tFV8D8-m75/s1600/Miniature%20pots.JPG" width="212" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">You can get them from AliExpress, they work fine. These pots are sealed so no dust can get in.</div><div style="text-align: center;"><br /></div><div><div><b><span style="color: red;">Adding extra's (like an LED and 2nd Audio input):</span></b></div><div>As you can see there's only one audio input but it is easy enough to add more inputs. You can simply connect them through a 100K resistor to pin 9 of the TL074 and they will be summed together. You can also put in more CV inputs if you wish by connecting them through a 100K resistor to pin 2 of the TL074.</div><div>&nbsp; &nbsp;The trimpots for the Offset control could actually be left out. They are not really necessary. They are part of the design because the early versions of the CA3080 chip (which was originally used in this filter) had quite a bit of variation in their offset voltages. But the latest generations don't have that problem anymore. I left the trimmers in because I stayed true to the schematic but it's up to you. The filter should work fine without them. Should you take them out then you can remove the trimmers and the 100K resistors in series with the wipers. Leave the 22 Ohm resistors to ground in place.</div><div>&nbsp; &nbsp;Finally we have an opamp left unused! We have to do something with that right? :-)<br /></div><div>I always like to <span style="color: #fcff01;">include a LED</span> if I can, so I altered the layout a little and made a jumpwire from the envelope input to pin 3 of the TL072. The green wirebridge from pin 10 of the TL074 needs to be lengthened and soldered straight to the bottom strip (X). Now we have configured the opamp as a voltage follower or buffer so we can connect a Bi-coloured LED to it without drawing any current from the envelope input. I used a big 4K7 resistor as current limiter so the LED will only be the brightest with the highest voltage. Below is the layout to show this alteration.&nbsp;</div><div><br /></div></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKRzlcGYR9kqDIrgfpU0dyOMUbzvJN3RtMI-EVpHlUGzPfCYH4fWiwE-BrqdTYdDXQ3uiwhQiBohH_JA8bdFycZBeJVuiVQShAVM-Jx9ZLCfpzZFalAdu3Nk2p5SGaMULc59wm_tTDY-cJR5Yls8fQ6-Ed3UBqBduECl1V0vx-6Uoz-Ybs1kFYiEI0fb8l/s3853/VCF-1%20with%20LED.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3131" data-original-width="3853" height="260" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKRzlcGYR9kqDIrgfpU0dyOMUbzvJN3RtMI-EVpHlUGzPfCYH4fWiwE-BrqdTYdDXQ3uiwhQiBohH_JA8bdFycZBeJVuiVQShAVM-Jx9ZLCfpzZFalAdu3Nk2p5SGaMULc59wm_tTDY-cJR5Yls8fQ6-Ed3UBqBduECl1V0vx-6Uoz-Ybs1kFYiEI0fb8l/s320/VCF-1%20with%20LED.jpg" width="320" /></a></div><br /><div>The components for this change are not listed in the Bill of Materials because this was done as an after thought, but it's only a LED and a resistor. I used a red/blue bi-coloured LED.</div><div><br /></div><div><b><span style="color: red;">ABOUT THE AC/DC SWITCH:</span></b></div><div>You may have noticed the audio input of the filter has an AC/DC switch in it. This is provided for instances where the full audio bandwidth of the signal is desired. DC coupling allows very low notes to pass through uninhibited by the input capacitor. This is actually the only filter on this website (apart from the ARP2600 LPF) that doesn't have a capacitor in the audio path, when switched to DC that is.</div><div>A DC signal can pass straight through the filter without ever encountering a capacitor so the filter can actually process a control signal! This opens up an entirely different can of worms. (In a positive way.)</div><div>For example you could patch the CV output of a sequencer through the Lowpass mode of this filter before it goes into a VCO. If you then modulate the cutoff frequency with an LFO you can create some really spacey effects.</div><div><br /></div><div><b><span style="color: red;">CALIBRATION:</span></b></div><div>This is the procedure for the V/Oct. tracking of the filter in full self oscillation:</div><div>Connect the lowpass output to your VCA so you can hear the signal. Be careful, the self oscillation signal is quite loud! (Very loud in fact)</div><div>Connect a keyboard or other V/Oct. source to the 1V/Oct. input of the filter.</div><div>Put the filter in self oscillation by turning the resonance full clockwise and adjust the V/Oct trimmer for as close to a one Volt per Octave interval as possible. Go between C2 and C3 on the keyboard for instance and turn the trimmer to get the best result. Use the Frequency Fine control to help you tune the oscillator to the right notes, if you kept this potmeter.</div><div><br /></div><div>About the trimmers.... what I actually did was put them in the middle position and just leave it at that. There really is nothing to trim because the modern AS3080 chips don't have erratic offset voltages in their output like the old CA3080's used to have. That's why this option is built into this filter, to trim away the offset from the CA3080's but with the new AS3080 there is no offset voltage.</div><div>So I didn't do any trimming and the filter works fine but I'll give you the procedure anyway, but as far as I'm concerned, you can ignore it.</div><div>Here is the procedure as mentioned in the official article:&nbsp;</div><div>Put the trimmers in the middle position. With multiturn trimmers you start turning them untill they start clicking. Then turn back and count the number of turns until the wiper is at the other side and you hear it clicking again. Now turn the wiper half the number of turns you counted. Then it's in the middle position. You could also just measure the voltage coming from the wiper and turn until it's at zero Volts. Then it's in the middle too.</div><div>Connect a square/pulse wave to the filter input and monitor the Lowpass output with an oscilloscope. Now check for DC deflection as you turn the Frequency Cutoff potmeter through its range. Adjust the trimmer to get the least DC deflection at the output.&nbsp;</div><div>The trimmers are interactive (they influence eachother) so you may have to go back and forth between them a few times.</div><div><br /></div><div>There should really be very little to trim. As I mentioned earlier, the filter will actually work fine even without these offset trimmers and with the AS3080 there shouldn't be any offset voltage to speak of.</div><div>However they must be set to the middle position so they don't add offset to the signal unintentionally.</div><div>Check your filter output on an oscilloscope (set audio in to DC) and make sure there's no DC offset.</div><div><br /></div><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures I took during the build proces:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv7IIR0ATNOB93sMYIA_FrcV186GeeRvRwZjkgB3bWdZZ_5c20LfjyTGUfDd4oQe0J5oDm5elDQKX0ARAffzQuV87Ghdgm1vOCPhFeqXXinehPXeBc5wbnMtP0lmMYgxultef6hf6vSt3Fr2NFSoczoTC2ZUVVN8rkiZ9QDxxc7Y2mHa1xe3OC32-Ocuzy/s3186/Wirebridges%20installed%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="3186" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv7IIR0ATNOB93sMYIA_FrcV186GeeRvRwZjkgB3bWdZZ_5c20LfjyTGUfDd4oQe0J5oDm5elDQKX0ARAffzQuV87Ghdgm1vOCPhFeqXXinehPXeBc5wbnMtP0lmMYgxultef6hf6vSt3Fr2NFSoczoTC2ZUVVN8rkiZ9QDxxc7Y2mHa1xe3OC32-Ocuzy/s320/Wirebridges%20installed%20Ps.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaj4aVyTagty7sMPxFXftmF7959-6gaodn1NEgNfdJBuXtIKCSEQ1K8-cvUKcrSlAPMcArh9XB8UEX4QKFH1bs6PZ-LS72kGRhvfuJSHmQPoJyupmzxDgIBy4tULha2orVmRsJkfCz52IHx0bK-e2zeg-PkxN0RxbK4usx6yVDpCvFtUsdUdJohyphenhyphenKJZDO2/s4000/Stripboard%20finished%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaj4aVyTagty7sMPxFXftmF7959-6gaodn1NEgNfdJBuXtIKCSEQ1K8-cvUKcrSlAPMcArh9XB8UEX4QKFH1bs6PZ-LS72kGRhvfuJSHmQPoJyupmzxDgIBy4tULha2orVmRsJkfCz52IHx0bK-e2zeg-PkxN0RxbK4usx6yVDpCvFtUsdUdJohyphenhyphenKJZDO2/s320/Stripboard%20finished%20Ps.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjID4_EwI7yk5zRAWdQTqmuPv6ZTQ8Nc-WA7NPTlyxhqiX-iG4pNgcYEPQVScwgG4YR20VzJsPt5WeAqWDslzE-afefgjXWTZd4IDhgE26NrPwaRilceKkUbAqKr4aIT75jZwV359hDilUo7yyZD_yqFWg8K-WXO_GlPnniDvUqLgcArFcRcl1yK-yy25pC/s3929/Stripboard%20wired%20up%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="3929" height="183" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjID4_EwI7yk5zRAWdQTqmuPv6ZTQ8Nc-WA7NPTlyxhqiX-iG4pNgcYEPQVScwgG4YR20VzJsPt5WeAqWDslzE-afefgjXWTZd4IDhgE26NrPwaRilceKkUbAqKr4aIT75jZwV359hDilUo7yyZD_yqFWg8K-WXO_GlPnniDvUqLgcArFcRcl1yK-yy25pC/s320/Stripboard%20wired%20up%20Ps.jpg" width="320" /></a></div><div><br /></div><div>As long as I was waiting for the new powder coated aluminium to come in the mail, I thought I'd make a template for the panel out of cardboard, so I can mount all the components in it and see if all the wiring is long enough. As you can see I changed my mind about the switch placement and I needed to lengthen several wires but it all fits nicely behind a Kosmo sized panel of 20 x 7.5 CM. I want to install this filter in my DIY synthesizer, not my Eurorack system. I think, if you want to fit it behind a eurorack panel, you have to make it a bit wider still.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNprRsArn7kLYEXJAd-BpEmBtaePQsuEG81594QhTCiB5RmP4ny-q7YwDjB2nA7hAdIFifR_4TSbb-z60lzZDRnOgVgN-SPnPmnxM5MEodxKfFgN6BPwrxS1nTqmi6_sqcjBceyGAe40Q3IpWKdALIdIA_o5YQwRJaLiYByS5zKIpZxyzc7hkPDHfteSof/s3373/Panel%20template.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3373" data-original-width="1363" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNprRsArn7kLYEXJAd-BpEmBtaePQsuEG81594QhTCiB5RmP4ny-q7YwDjB2nA7hAdIFifR_4TSbb-z60lzZDRnOgVgN-SPnPmnxM5MEodxKfFgN6BPwrxS1nTqmi6_sqcjBceyGAe40Q3IpWKdALIdIA_o5YQwRJaLiYByS5zKIpZxyzc7hkPDHfteSof/s320/Panel%20template.jpg" width="129" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOZ7pCl_GegDo5RkDYtPM4oN4GNjg-iB2b9Z-522BeZFQ7EuinEWHxmYMgX7pRV7a7ddxG2IZudxF_ROIeoTg64TvvapNbfzWNIsNE5nJGJP19JV_giLz-cn5Mm_C9lNS9Bq_xSTlraJWOIhdtjAZRRJ6biD3Yn9IMQTaevP38BIWaqkNTcGJnOs8JS_KM/s4000/Panel%20ready.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOZ7pCl_GegDo5RkDYtPM4oN4GNjg-iB2b9Z-522BeZFQ7EuinEWHxmYMgX7pRV7a7ddxG2IZudxF_ROIeoTg64TvvapNbfzWNIsNE5nJGJP19JV_giLz-cn5Mm_C9lNS9Bq_xSTlraJWOIhdtjAZRRJ6biD3Yn9IMQTaevP38BIWaqkNTcGJnOs8JS_KM/s320/Panel%20ready.jpg" width="180" /></a></div><div><br /></div>Here's the finished module all ready to go mounted in my DIY synthesizer: I did all my testing running this filter on +/-12V and it was absolutely fine. But in my synthesizer I have two powersupplies, one for +/-12V and one for +/-15V, so I decided to connect it to the +/-15V supply for permanent use.&nbsp;</div><div>(Boy, does this thing sound good. I love it!)</div><div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy5CpwZh49h4G-ZGe8Jprg-5CQKnLKhocacw-sMkrn71-oBHA9G9GbFaOOibqqgo5Z47FgLXvPYGPeHu-08u0dxJTAAheVpsg4rh2bYQvzKt95bAl6Jq0uj0gnd7AIhIywAn0i-9mWy0hH-mmQSS7d6-LNBkJepEcsMTneGTQVF_BxZAWmgnIyMB9lmp2q/s4000/Finished%20module.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy5CpwZh49h4G-ZGe8Jprg-5CQKnLKhocacw-sMkrn71-oBHA9G9GbFaOOibqqgo5Z47FgLXvPYGPeHu-08u0dxJTAAheVpsg4rh2bYQvzKt95bAl6Jq0uj0gnd7AIhIywAn0i-9mWy0hH-mmQSS7d6-LNBkJepEcsMTneGTQVF_BxZAWmgnIyMB9lmp2q/s320/Finished%20module.jpg" width="180" /></a></div><br /><div>I wrote the labels with a white acryllic pen. I got new pens and this one is not as scratch resistant as the old pens I used to have so after I finished labeling everything I sprayed the panel with a layer of clear lacquer.</div><div><br /></div><div>The stripboard is mounted behind the panel with a piece of plexiglass as an experiment. I bent the plexiglass at both ends so it grips the stripboard like the fingers of a hand. I glued two little pieces of plexiglass at the ends so the stripboard can't slide out and I secured it with hot glue. Then I drilled a 3mm hole through one end and mounted it to the panel with an M3 bolt. I also used superglue to secure it and keep it from rotating should the bolt get loose. It's over elaborate and I won't use this method again. It's just that I had no room for L-Brackets on the stripboard.</div><div><br /></div><div>When I first tested the filter I found that the Frequency control wasn't working. The Resonance was fine and I could see on the oscilloscope that the filter was doing it's thing but no Frequency control. I took my scope probe and tested the legs of the transistor pair and sure enough. Transistor Q2 was not working. So I put in a new matched pair of transistors and now everything was fine. It all worked as it should. Strangely enough the transistor was not faulty. It must have been a bad connection.</div><div><br /></div><div>Here is a video of me testing the filter and the different outputs. It's a video I also uploaded to my YouTube channel.</div><div>I found with testing that the Lowpass sounds best with a squarewave on the input. The High- and Bandpass filters sound the best when you use a Sawtooth wave on the input.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/nfL-Lz-0RnQ" width="320" youtube-src-id="nfL-Lz-0RnQ"></iframe></div><div><br /></div><div>Here's a little test video with a demonstration of the extra CV input I installed (with level potmeter). I have a sinewave connected to the second CV input. The rest is like the previous video:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/HS_h1KrNpUA" width="320" youtube-src-id="HS_h1KrNpUA"></iframe></div><div><br /></div><div>Okay, that's it for now. Enjoy building this filter. It's a really good one!</div><div>If you have any questions about this or other projects then please comment below or post your question in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group</a> for this website.</div><div><br /></div></div><div><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-8282572294195058326
title: Synthesizer Build part-57: X-4046 VCO by THOMAS HENRY.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/04/X-4046%20VCO.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>A fantastic sounding VCO with 5 waveform outputs and an amazing hard sync sound! Quite easy to build too. This is a Kosmo project, not Eurorack. At least not this particular article. But this VCO will run fine on a dual 12V powersupply.</p><div style="text-align: left;">PCBs for this VCO are currently out of stock.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Finally a new VCO project on my website. These are always the most popular projects as I can see in the data I get from Google. And this is a really nice one too.&nbsp;</div><div style="text-align: left;">It's a favorite among Psy-Trance and Techno producers! I'm reliably informed by a top Dutch psytrance producer that the <span style="color: #fff2cc;">hard sync and FM functions of this VCO are better than that of the Nord Lead</span>. He regards this VCO as his secret weapon creating unique sounds not heard on other albums.</div><div style="text-align: left;">It has no less than five waveform outputs. The usual ones: Square/Pulse (with PWM), Sine wave, Triangle wave and Sawtooth wave and then there's the Rampoid wave. This is a mixture of the Triangle and the Sawtooth waves and there's a potmeter to go between the two which makes for some really cool wave shapes. See the scope pictures below.</div><div style="text-align: left;">One little side note though, this VCO is known for being difficult with tuning. It'll tune fine but the tracking over the octaves is not very precise. It's good enough to make the VCO useable of course but you will spend some time tuning and it won't be perfect. Just so you know!</div><div class="separator" style="clear: both; text-align: left;">[Edit: Dec 2025: I just want to add to that last remark that I just finished building this VCO using all PCB's and using a Texas Instruments CD4046 and I got it in tune over 5 octaves with +/-3 cents so that ain't half bad. I used just the V/Oct trim and the fine tune pot on the panel to get back on the exact notes and if the high octaves were a bit off I used the HF-trim, which on this VCO actually works. I also built a 4046 Super VCO with the suboscillator from the VCO Maximus and that one tuned very well too.]</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div style="text-align: left;">When I was researching the VCF-1 filter (project 56) I found the <a href="https://www.birthofasynth.com/Thomas_Henry/Pages/X-4046.html" target="_blank">'Birth Of A Synth'</a> website with all of Thomas Henry's projects on it and in the list was this VCO. I came across this design before and I always wanted to build it because the TH VCO-555 was also such a good design but also because of this VCO's famous Hard Sync sound.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNhE8NIOXXwRZiF93rhdIogP5LhLyWuSADKMm067nWXOb8iFDx5te76jk2a-icj9sijwWrf2ILE2LYaPM_crzrCul_ID84w5MOhsZ6Dr6CU0Q9Naxq7E4QxxsGcEYeRVPTYO-aHCNfC7ro_mSV7QOtG5sH1mkeRM_-z6T2OW62Dnv29tyiJDwETHvt3XCq/s4000/VCO%20Faceplate%20design.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNhE8NIOXXwRZiF93rhdIogP5LhLyWuSADKMm067nWXOb8iFDx5te76jk2a-icj9sijwWrf2ILE2LYaPM_crzrCul_ID84w5MOhsZ6Dr6CU0Q9Naxq7E4QxxsGcEYeRVPTYO-aHCNfC7ro_mSV7QOtG5sH1mkeRM_-z6T2OW62Dnv29tyiJDwETHvt3XCq/s320/VCO%20Faceplate%20design.jpg" width="180" /></a></div><div style="text-align: center;"><span style="font-size: x-small;"><br /></span></div><div style="text-align: center;"><span style="font-size: x-small;">The finished module.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;">The 'Birth of a synth' website also lists another VCO, the VCO-1 but if you look at the schematic it's just a scaled down version of the X4046 so I went with this design.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">Below is the schematic for this VCO. The CD4046 is an interesting chip to use for a synthesizer VCO. It has an onboard voltage controlled oscillator and two types of phase comparators. The IC has been used in some very cool Eurorack modules too, among them the Wiard Wogglebug.</div><div style="text-align: left;">The 4046 produces 2 halfs of a sawtooth wave coming out of pins 6 and 7 depending on the state of the VCO output of the chip (which is a squarewave). When it's high, pin7 is ramping. When it's low pin 6 is ramping. So instead of picking the signal from the output of the chip, Thomas Henry picked them straight from pins 6 and 7. These are then combined to form a composite sawtooth wave and that's why we have to set a trimmer to match them up to eachother to form one wave. The triangle wave is made by inverting one of the sawtooth halfs and applying an offset voltage to it to glue them together to form a triangle wave. This has the side effect of creating those spikes you see at the top and bottom of the triangle wave. Once we have the triangle wave it isn't too difficult to turn it into a sinewave by using the tried and tested transistor pair converter method. The squarewave is made by sending that sinewave into an opamp comparator which flips polarity everytime the sinewave goes over a threshold voltage set by the PWM opamp. Varying this voltage produces a change in the dutycycle of the squarewave.</div><div style="text-align: left;">The opamp used in the exponential converter, with the inputs of the VCO, is again an interesting one, the LF442. This is a modernised version of the LM1458. It has the same input characteristics of the LM1458 but only draws one tenth of the current. In addition the well matched high voltage JFET input devices of the LF442 reduce the input bias and offset currents by a factor of 10.000 over the LM1458. This ensures very low voltage drift and it also has very low equivalent input noise voltage for a low power amplifier. Seems like a good choise then ^___^</div><div style="text-align: left;">New LF442's are very difficult to find and I struck it lucky when my local electronics shop still had two of them in stock but as an alternative, the 4558 will do nicely or the TL072. They all work fine in this VCO. I tested them myself.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here are the main features of the X-4046 VCO:</div><div style="text-align: left;">Exponential control and modulation.</div><div style="text-align: left;">Linear modulation.</div><div style="text-align: left;">Five unique waveform outputs: triangle, sawtooth,pulse with pulse width modulation, sine and variable rampoid. All waves are roughly 10Vpp through zero. (+/-5V)</div><div style="text-align: left;">Frequency range goes al the way from roughly one cycle every 24 seconds (41.7mHz) upto around 16.4kHz. so this VCO is also usable as a LFO.</div><div style="text-align: left;">And as the article in 'Birth of a Synth' states; one of the finest hard sync effects ever heard from a VCO.</div><div style="text-align: left;">The original schematic has the circuit running on a dual 15V powersupply but I changed it to dual 12V power for this project.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: #fcff01;">THIS VCO WILL RUN ON BOTH +/-12V OR +/-15V.</span> I first built my VCO to work on +/-15V but I also tested it on +/-12V and it works just as well. Even the tracking wasn't much different when I switched to +/-12V so because most people build for 12V (Eurorack and Kosmo) I revised the schematic. Some waveforms were a bit lower in amplitude though. Most notably the sinewave which dropped quite a bit so for that reason R18 and R19 going from Q4 and Q5 to the opamp were changed from 10K to 15K. Also the output for the pulse wave needed to be increased so I changed those output divider resistors to 2K2 for both.&nbsp; The changes are made in the schematic and layouts.</div><div style="text-align: left;">Schematic:</div><div style="text-align: left;"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1iuiFCW77FQj6BarFJ7w1FMVKWZZ1ljIm92h-ZGGisiDPBqJS6Nx6qTQbC3Hyz1IhY-L9vJPJtvGWW59DI2MB1r4SV5moYDv1SJsycZA1bWO2T_wChWglU9_oig2Vn4Qrl2K8x-BXZ1gVzry7wJgpPvNTjw1DNyHScDtPiB-lu8XTVBcKT2s6hCQt-srm/s2953/X-4046%20VCO%20full%20schematic%2012V%20version.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1442" data-original-width="2953" height="156" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1iuiFCW77FQj6BarFJ7w1FMVKWZZ1ljIm92h-ZGGisiDPBqJS6Nx6qTQbC3Hyz1IhY-L9vJPJtvGWW59DI2MB1r4SV5moYDv1SJsycZA1bWO2T_wChWglU9_oig2Vn4Qrl2K8x-BXZ1gVzry7wJgpPvNTjw1DNyHScDtPiB-lu8XTVBcKT2s6hCQt-srm/s320/X-4046%20VCO%20full%20schematic%2012V%20version.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Below are the layouts for this project. As always they are verified. I used them for my build and I can tell you it worked flawlessly right from the get go. Not a single mistake! All I had to do was trim the waveforms into the right shape and the VCO was up and running. Oh and tune it for octave tracking of course. I have adapted the layout for use with +/-12V.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's the wiring diagram. We have 7 potmeters, 10 in- and output sockets and a toggle switch to wire up. It took me an afternoon and the next morning to get it done. I used 1M potmeters instead of 100K for all but the Frequency Coarse and Fine controls. The value of the panel potmeters makes no difference except the 'Skew' potmeter. That one should be 500K or higher. (I also used a 1M for that one) but I later used a 100K in my Eurorack version and that works fine too.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg18_rzZk_JONgGumn8VOBmIh1RqXGA97ayK760f5lEW3E-ADgxgUuGTY_8u3srqyso1d0BM_UvthxNCtDUbaz-LiMF0xbq8rKl0vrIzH8xbVSXHsm24Edy1Uexjd4sQeWYDrtbSRsXnM5Od6Jzx_07EBEPka7321Io2Zjb7Q1yS7qmdSlECgYpO_tiqvR4/s9514/TH%20X4046%20VCO%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5306" data-original-width="9514" height="178" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg18_rzZk_JONgGumn8VOBmIh1RqXGA97ayK760f5lEW3E-ADgxgUuGTY_8u3srqyso1d0BM_UvthxNCtDUbaz-LiMF0xbq8rKl0vrIzH8xbVSXHsm24Edy1Uexjd4sQeWYDrtbSRsXnM5Od6Jzx_07EBEPka7321Io2Zjb7Q1yS7qmdSlECgYpO_tiqvR4/s320/TH%20X4046%20VCO%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Stripboard only view:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg__hF3DXrjNxfv43L96g5VVtwMpDOOk5RC4pQWocP4siQMP3af5MuPd9mV7NBpzrp4s0eUXggfi3ntQpQ_3_HfUlRvomO8uLS7oJmcMDuAzXHFGQkJ2p9nEgUp0a_DcZrQ6OP_5Gr2Sxfci6Jl9j7l22lSOJ_QwY_yvnp2md_4ioc4StNTofy7AdEp3P9u/s6000/TH%20X4046%20VCO%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2710" data-original-width="6000" height="145" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg__hF3DXrjNxfv43L96g5VVtwMpDOOk5RC4pQWocP4siQMP3af5MuPd9mV7NBpzrp4s0eUXggfi3ntQpQ_3_HfUlRvomO8uLS7oJmcMDuAzXHFGQkJ2p9nEgUp0a_DcZrQ6OP_5Gr2Sxfci6Jl9j7l22lSOJ_QwY_yvnp2md_4ioc4StNTofy7AdEp3P9u/s320/TH%20X4046%20VCO%20-%20Stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">I had some difficulty in placing the matched transistor pair Q4 and Q5 near to the opamp they need to be connected to, so I had to use some jump wires for that. The jumpwires are not shown in the layout. Instead I have marked the places where they need to go with 2 orange circles with the number 5 meaning this point needs to be connected to pin 5 of IC-4 and 2 yellow circles marked with the number 6 which needs to connect to pin 6 of IC-4. I used shielded wires and I connected the outer braiding of the wires to the ground strip underneath IC-4 (strip X) and these points are also marked with green circles with numbers in them. (Only ground the wires at one end)</div><div style="text-align: left;">However, you don't have to use shielded wires. Normal jump wires will work fine too. I just played it safe because the wires pass right over IC-1 <u>but you can save yourself the trouble.</u></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Here's a look at all the cuts and wirebridges that need to be put in place before you start putting in the components. There are 45 wirebridges to solder in:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjc0rFZLc9DaT6ek06VtC5ufzOOuwVbXbMI-4Zy2n4BL8kNEWUA52dZGH1c4l5EQb65VewE_tVh3e_44cMXgKUPWqd8hYXQn2cgxBnnXS4-JE466D23KEVjVvc7drAOgV7RSaX4uG0bQa9T8ZDe3Xb0VAmvyRn4WWw5ietARE0q1c6pK6w8xhtmkxyK0eeK/s6149/X-4046%20VCO%20by%20TH%20cuts%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2969" data-original-width="6149" height="155" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjc0rFZLc9DaT6ek06VtC5ufzOOuwVbXbMI-4Zy2n4BL8kNEWUA52dZGH1c4l5EQb65VewE_tVh3e_44cMXgKUPWqd8hYXQn2cgxBnnXS4-JE466D23KEVjVvc7drAOgV7RSaX4uG0bQa9T8ZDe3Xb0VAmvyRn4WWw5ietARE0q1c6pK6w8xhtmkxyK0eeK/s320/X-4046%20VCO%20by%20TH%20cuts%20wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">A close-up of where the two jumpwires need to go. This image doesn't show the whole stripboard just a zoomed-in bit to show where the wires must go.:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsfnntPB_auiTyyE82wzAjLVYDm9C-DBFxZrE8ma1kxUZ1gCazlfS2rO-MthpTw2cApk_B_b1ogM2reHN-rFetbW0UNnixGnqw9lYaM66A4ubNdfaepW8b566viU-SlDJlYFyPwLGulos1MMf22CV2w1n7rg97J8W3Kiugz5PR0ZCb4jJtbE9He_7-E6ly/s4010/X-4046%20VCO%20by%20TH%20cuts%20wirebridges%20jump%20wires.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2358" data-original-width="4010" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsfnntPB_auiTyyE82wzAjLVYDm9C-DBFxZrE8ma1kxUZ1gCazlfS2rO-MthpTw2cApk_B_b1ogM2reHN-rFetbW0UNnixGnqw9lYaM66A4ubNdfaepW8b566viU-SlDJlYFyPwLGulos1MMf22CV2w1n7rg97J8W3Kiugz5PR0ZCb4jJtbE9He_7-E6ly/s320/X-4046%20VCO%20by%20TH%20cuts%20wirebridges%20jump%20wires.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Cuts only view, seen from the component side. As always, mark the cuts on the component side first with a waterproof Sharpie or Edding400 and then put a pin through the marked holes and mark them again on the copper side. Then cut the copper strips at the marked places. That way you have the least chance of making mistakes.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirJgchYUwH9aSpFMkFUF5gWYwCriR6M8x1pSE7rM4ZrAG7Z5-7HNPca-ZdbI5VL73eBmmUl0E8AuUNbg9p31W6SN2EKAewH0GBwJEKwiZ_CeKoV7v8ieVfWYD-21q0fCY15aH9y3g-lC1sXfIb75_vFUC2HW4JiilW-r72i4FZTjhHS6S3A5hE-8QcvNq9/s6372/X-4046%20VCO%20by%20TH%20cuts%20component%20side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3108" data-original-width="6372" height="156" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirJgchYUwH9aSpFMkFUF5gWYwCriR6M8x1pSE7rM4ZrAG7Z5-7HNPca-ZdbI5VL73eBmmUl0E8AuUNbg9p31W6SN2EKAewH0GBwJEKwiZ_CeKoV7v8ieVfWYD-21q0fCY15aH9y3g-lC1sXfIb75_vFUC2HW4JiilW-r72i4FZTjhHS6S3A5hE-8QcvNq9/s320/X-4046%20VCO%20by%20TH%20cuts%20component%20side.jpg" width="320" /></a></div><div><br /></div><div style="text-align: left;">And here's the Bill of Materials. For the PTC I used the same one as I used on the 555-VCO. See <a href="https://www.eddybergman.com/2020/12/synthesizer-build-part-37-thomas-henry.html" target="_blank">project 37</a>. That article has links to the webshop where I got them from They are 3300ppm instead of 3500ppm but that 200ppm difference you can ignore. It works just fine. If you don't have a 2K PTC then just put in a 2K resistor instead.&nbsp;</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPiXxfV31alH51dPCzTKrkDxt-h2yJtMvD43sJyZLW_CBuPjjdPe10MQFxFVmR6h7tUx3412hDpRhO3H3nxvAsNbnT3yNWAXaHJsD4tYTA7c3jm2NwQVS1Zg16HpMkFIFzmLQzL_RatVF7FHIBgegZ4Y_fdAxBia6_BpA0xUXFHsBJ7wmnwAmDFE6xqUav/s1279/X4046%20VCO%20bom%2012V%20version.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="1279" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPiXxfV31alH51dPCzTKrkDxt-h2yJtMvD43sJyZLW_CBuPjjdPe10MQFxFVmR6h7tUx3412hDpRhO3H3nxvAsNbnT3yNWAXaHJsD4tYTA7c3jm2NwQVS1Zg16HpMkFIFzmLQzL_RatVF7FHIBgegZ4Y_fdAxBia6_BpA0xUXFHsBJ7wmnwAmDFE6xqUav/s320/X4046%20VCO%20bom%2012V%20version.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><b><span style="color: red;">BEST CHIPS TO USE:</span></b></div><div>It is mentioned in the article that certain 4046 chips are better for tuning than others. I used a Texas Instruments CD4046. It was good enough for me but if you want the best chip for this circuit the ones to get are: National CD4046, Fairchild CD4046 or the Motorola MC14046. This last one is the best one you can get. They are pretty difficult to find though so you'll probably end up doing as I did a go with the Texas Instruments CD4046 and take the tuning difficulties for granted. You'll still end up with a fantastic and very useable VCO. Actually, the stripboard version took a bit of time to tune but I later made eurorack PCBs for this VCO and they tuned just fine with Texas Instrument IC's. You can have the occasional bad chip in a batch though, so if you struggle to get it tuned change out the 4046 for another and try again.&nbsp;</div><div><br /></div><div style="text-align: left;"><b><span style="color: red;">THE BUILD PROCESS:</span></b></div><div style="text-align: left;"><div>As I mentioned before I had to use jump wires on the stripboard and because the wires pass right over, or near, the CD4046 I chose to used shielded wires. I connected the shielding to the bottom right ground strip (X). The outside shielding of the wires must only be grounded at one end. <span style="color: #fff2cc;">At first I used unshielded wires and actually it will work just as well so you don't have to used shielded wires. I just played it safe.</span></div><div>The transistor pairs need to be matched because one of the pairs makes up the current mirror for the 1V/Octave tracking and the other pair determins the shape of the sinewave. It's a classic triangle to sinewave converter design. I matched them by measuring the Hfe on my multimeter and choosing two that have the same value. You really should use the Ian Fritz method though. See the TB-303 filter project for an in depth explanation of how that works.</div><div>Just like in the 555 VCO, Thomas Henry uses a 2K PTC for temperature compensation. Luckily I still had a few left so I didn't need to order any. I recently ordered ten more because they are out of production. So when the shops are out of stock, that's it. No more PTC's. At least, not these ones.</div><div>After I had finished making the stripboard, I made the front panel and put in all the potmeters and sockets. I made a special mounting bracket for the stripboard out of plexi glass. I took a small strip of it and bent it at one end in an L shape, using a heat-gun. then I glued small squares of plexiglass to the top and bottom ends so the stripboard could sit inbetween them. Then I hot glued the stripboard to the bracket. It works very well. Here's a front and back view picture to illustrate:</div></div><div style="text-align: left;">&nbsp;</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtlbwT8Uf5Z_A3D6CDzW_GBNdBDRRfXSZRXzR6Pl-lwSz-pROXSChXIhDnHES_WJI_S1Uq6-M3MCMAGz68LwqVdUQ_ORLOc_nsZNo1BmhR2-duItsXQr2qWMrJilAVtLLYlwZYJFe272RVcPMw9arGHBPEJREhWuDO0qXtcprT_2EmVy9BdZmEiDfALNhH/s4000/Plexiglass%20L-bracket%20solution.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3899" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtlbwT8Uf5Z_A3D6CDzW_GBNdBDRRfXSZRXzR6Pl-lwSz-pROXSChXIhDnHES_WJI_S1Uq6-M3MCMAGz68LwqVdUQ_ORLOc_nsZNo1BmhR2-duItsXQr2qWMrJilAVtLLYlwZYJFe272RVcPMw9arGHBPEJREhWuDO0qXtcprT_2EmVy9BdZmEiDfALNhH/s320/Plexiglass%20L-bracket%20solution.jpg" width="312" /></a></div><br /><div style="text-align: left;">Here are some more pictures from the build process:</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I had already started putting in some components before I remembered to take a picture of the stripboard with just the wirebridges.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqVgg_-DALoxtCoNNCyySKELaxgPV5Lxh_1CTBk7FcJk6vsXj9bczOhoHEeqQxHF3qUeat3JmUYeKbcFze36mAgJgIrrCDD55B8jpLROReT6buktSsV171_5ovH7R4Ls0vWB-DyPYKKwgr823TiEgkID6kKDxj7pJxRTW_82bTfWLkj5v3BinfLW3Yj7Oa/s3436/X4046%20VCO%20wirebridges%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1845" data-original-width="3436" height="172" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqVgg_-DALoxtCoNNCyySKELaxgPV5Lxh_1CTBk7FcJk6vsXj9bczOhoHEeqQxHF3qUeat3JmUYeKbcFze36mAgJgIrrCDD55B8jpLROReT6buktSsV171_5ovH7R4Ls0vWB-DyPYKKwgr823TiEgkID6kKDxj7pJxRTW_82bTfWLkj5v3BinfLW3Yj7Oa/s320/X4046%20VCO%20wirebridges%20finished.jpg" width="320" /></a></div><div><br /></div>Stripboard finished but chips not yet mounted in their sockets. In this picture you can see the jumpwires and because this was in the testing phase they are normal not shielded wires. I later put in shielded to see if there was any difference but there wasn't so you can just use normal jump wires.<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgG8lBQURLQXJSFOqo2buSy8Ek_UONmJ8oQl1t3y1BzSVXPB5QnlqBJiK4U57KIJDFkUNZXO1IYu60MATS9q7Nepz8BBhAw58FXleH1AyWl7WeSBppaHAJlTAtweBzXXaIhl7MF0rV_icSJwse7DaY9akHfRY1AgSqKefyZqgb_Q8zb7L2IG7-YawNREuhB/s3680/X4046%20VCO%20stripboard%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2028" data-original-width="3680" height="176" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgG8lBQURLQXJSFOqo2buSy8Ek_UONmJ8oQl1t3y1BzSVXPB5QnlqBJiK4U57KIJDFkUNZXO1IYu60MATS9q7Nepz8BBhAw58FXleH1AyWl7WeSBppaHAJlTAtweBzXXaIhl7MF0rV_icSJwse7DaY9akHfRY1AgSqKefyZqgb_Q8zb7L2IG7-YawNREuhB/s320/X4046%20VCO%20stripboard%20finished.jpg" width="320" /></a></div><div><br /></div><div>Everything ready for wiring up. That took me an afternoon plus the next morning. All the socket grounds are connected together through one copper wire which then connects to ground on the stripboard.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRi_EY-MAA0NG-QPaTLUc86erjVJxjpEKlDSQPUCb6GjPKhRjUFw2FLhWIlqFGy6qPQiWtMWNiocTs7rL6Bo3leoKjw4J8SdSKncxmdMMjuFRSCeUZD5FubshAhCBO_1Nh-1Td2gJFxGXaXlwE0TA2gkPmDJcg7FMDMq-Is_e7apWp_2olj4XPDNLWSsSt/s4000/VCO%20backside%20but%20not%20wired%20up%20yet.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRi_EY-MAA0NG-QPaTLUc86erjVJxjpEKlDSQPUCb6GjPKhRjUFw2FLhWIlqFGy6qPQiWtMWNiocTs7rL6Bo3leoKjw4J8SdSKncxmdMMjuFRSCeUZD5FubshAhCBO_1Nh-1Td2gJFxGXaXlwE0TA2gkPmDJcg7FMDMq-Is_e7apWp_2olj4XPDNLWSsSt/s320/VCO%20backside%20but%20not%20wired%20up%20yet.jpg" width="320" /></a></div><div><br /></div><div class="separator" style="clear: both; text-align: left;">My faceplate design. Just white acryllic marker on black powdercoated aluminium, sealed with a clear lacquer coating, which is why it's so reflective :)</div><div style="text-align: left;"><br /></div></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijArOpgGpTyyUmsI8C4iPuTuV1VFw9P2Eg2ynzd8ux2b_kXwONZ95xf7uX1cCaUhWgEmBeAx1jZb22iCVgT-n9aTECmehb45SM8Y5xGAeFdeTKQP1wbX8zAC3URMmz90msy_iWaSmLyCXREp0X8TkxZLi1afh6AylFdK4uyebrKaXpuseToaKZAN7NnRjH/s4000/VCO%20Faceplate%20design.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijArOpgGpTyyUmsI8C4iPuTuV1VFw9P2Eg2ynzd8ux2b_kXwONZ95xf7uX1cCaUhWgEmBeAx1jZb22iCVgT-n9aTECmehb45SM8Y5xGAeFdeTKQP1wbX8zAC3URMmz90msy_iWaSmLyCXREp0X8TkxZLi1afh6AylFdK4uyebrKaXpuseToaKZAN7NnRjH/s320/VCO%20Faceplate%20design.jpg" width="180" /></a></div><br /><div>The finished VCO undergoing testing. I have a special power output on the side of my synth that I can use to test new modules. Very handy to have :)</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrbPt8QqY7LNJAP1Y_G4u_h-HyHEm6vv5hHDqHpb6Khyphenhyphen6ufPWM4YsGE-0pGjCkXbXh0ZSz31lM3aRjEGPbjPXbwYmA3BFeVtBDb0goy_ZAN0_mDUCvhHJlC2TGeBt7YDHekv2X-k4N7dqNaXJ-0-8ZoFnOEpt_rOmHQGELXUvF_6mnyRlbaYs8hA6Cc9xi/s4000/Finished%20module%20undergoing%20testing.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrbPt8QqY7LNJAP1Y_G4u_h-HyHEm6vv5hHDqHpb6Khyphenhyphen6ufPWM4YsGE-0pGjCkXbXh0ZSz31lM3aRjEGPbjPXbwYmA3BFeVtBDb0goy_ZAN0_mDUCvhHJlC2TGeBt7YDHekv2X-k4N7dqNaXJ-0-8ZoFnOEpt_rOmHQGELXUvF_6mnyRlbaYs8hA6Cc9xi/s320/Finished%20module%20undergoing%20testing.jpg" width="320" /></a></div><div><br /></div><div><b><span style="color: red;">CALIBRATING THE WAVEFORMS:</span></b></div><div>Calibrating the waveforms of this VCO is really straight forward.</div><div>For the different waveforms you just adjust the trimmers until the waveforms look good to you. Set the triangle wave first. Use the trimmers to connect the two halfs of the waveform. After that you can set the sinewave. Triangle connect does exactly what it says, it connects the upward slope to the downward slope. Very straight forward to set. One trimmer is for the upward slope and the other for the downward slope. You'll see frequency spikes appear on the top and bottom of the triangle wave. This is normal. They are so high in frequency that they can't be heard so ignore them.</div><div>You need to set the offset voltage for the Triangle and Sawtooth waves so that the zero Volt line goes nicely through the middle.</div><div><b><span style="color: red;"><br /></span></b></div><div><b><span style="color: red;">TUNING THE VCO:</span></b></div><div>Tuning the V/Octave tracking of the VCO is a bit counter intuitive so I made a little drawing to make it clear:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6uHc0EI1xFPyaq2g91E7MSvjbeyd8RmhrG7cVy2xu5jALd9z3ia_58rBVqN4C1gjCzFSzrvBUyeKAzMRcudNBySX6PmPaDYxWbny1PSszfcVQahzgatN9tZ2_9vQxsU6dHRB5deG5a8VDCe_C9mtg6gmw1IberrRl1WXLVDFujwCx4exLWTnq9jsSuNge/s3170/Tuning%20the%20X4046%20VCO.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1959" data-original-width="3170" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6uHc0EI1xFPyaq2g91E7MSvjbeyd8RmhrG7cVy2xu5jALd9z3ia_58rBVqN4C1gjCzFSzrvBUyeKAzMRcudNBySX6PmPaDYxWbny1PSszfcVQahzgatN9tZ2_9vQxsU6dHRB5deG5a8VDCe_C9mtg6gmw1IberrRl1WXLVDFujwCx4exLWTnq9jsSuNge/s320/Tuning%20the%20X4046%20VCO.jpg" width="320" /></a></div><br /><div style="text-align: left;">If you press C1 on the keyboard and use the frequency potmeters on the front panel and tune to C1 and you then press C5 and you get a higher note than C5, then your octave span is too wide. To counter that you need to trim the frequency up to narrow the frequency span. If you have C1 in tune and you press C5 and land on a lower note your frequency span is too narrow. Lower the V/Oct. frequency to widen it.&nbsp;</div><div style="text-align: left;">Do you see how counter intuitive this is? If the frequency of C5 is too high you need to increase the frequency with V/Oct trimmer. It took me a while to figure this out.</div><div style="text-align: left;">If you get the lower octaves nicely in tune but the higher ones are increasingly more cents off then you need to use the HF Trim potmeter to set that right. Just experiment with it, I think you can just lower the frequency to get it in line.&nbsp;</div><div style="text-align: left;">You will only see it work on octaves 5 and higher but the lion share of the tuning is just done with the V/Oct trimmer and the frequency potmeters on the front panel. The Course potmeter should end up at the 11 o'clock position.</div><div style="text-align: left;">With the first try I was fiddling and fiddling and I got absolutely nowhere. Then I thought I'd change out the X4046 chip and that was the solution. I had four CD4046 ICs from Texas Instruments and eventhough they were all from the same batch, some worked well and others didn't. Beware of that.</div><div>The make of your 4046 chip is important. Look at the text under the Bill of Materials for a sum up of the best chips for this circuit. Motorola works best, Texas Instruments is said not to work so good but I found that depends on the individual chip, as I mentioned before. The TI chips in my VCOs all work fine and I've got them in tune over 5 octaves with just a few cents between them.</div><div><br /></div><div>These are the test results Thomas Henry himself got when tuning his VCO to track over the octaves:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMjUbtx8Kj76KXGAPHL72kUrb_oIQmcAu8ojyzdq0jJKwPrqheo_0pS4VeSNMdj9vOmh-DsRHtQSsK7rM5AVePulxlaMpGhORYpLPuxcpqR8_Fh8KZoViqwyBDBfeigtZHS6A1m23r7efkHU27k_m6kPx9ZnloxesN1C5KcuNMEFpe8AtowVBvYflhtY6-/s1131/Spec%20sheet%20test%20results%20by%20Thomas%20Henry.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="716" data-original-width="1131" height="203" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMjUbtx8Kj76KXGAPHL72kUrb_oIQmcAu8ojyzdq0jJKwPrqheo_0pS4VeSNMdj9vOmh-DsRHtQSsK7rM5AVePulxlaMpGhORYpLPuxcpqR8_Fh8KZoViqwyBDBfeigtZHS6A1m23r7efkHU27k_m6kPx9ZnloxesN1C5KcuNMEFpe8AtowVBvYflhtY6-/s320/Spec%20sheet%20test%20results%20by%20Thomas%20Henry.JPG" width="320" /></a></div><div>Source: <a href="https://www.birthofasynth.com/Thomas_Henry/Pages/X-4046.html" target="_blank">Birth of a Synth website</a>.</div><br /><div><b><span style="color: red;">OSCILLOSCOPE SCREENSHOTS:</span></b></div><div>Here are the standard waveforms. The spikes you see on the triangle wave are a characteristic of the VCO as I mentioned in the schematic section. They are very fast and way beyond the human hearing range (80kHz or over) so not audible what so ever.</div><div>When I looked at the sawtooth wave I saw it had a bit of a wobble on the oscilloscope. However this changed to rock solid once I started playing the keyboard. Consequent versions I built of this VCO using PCB's all had this wobble but it goes away once you start playing the VCO with a keyboard.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqPwLmaV1lCFf7McFDYRwBac5HDrOtx1g0xRyv9suHZSYnSiRXQ313IYIQ5qFewbBzBfoLGf11jewMUTOkDoiy3-uvilGHQ0OQR4WHznUZo-25GRTj_Xu2bQugpAWIHZ2XFvLrZ5dniEdAeDephrjgTAODF03ebFD1Wx2L1IyzLc5B0XiGXkktylDUaals/s1600/Main%20waveforms%204046.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1440" data-original-width="1600" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqPwLmaV1lCFf7McFDYRwBac5HDrOtx1g0xRyv9suHZSYnSiRXQ313IYIQ5qFewbBzBfoLGf11jewMUTOkDoiy3-uvilGHQ0OQR4WHznUZo-25GRTj_Xu2bQugpAWIHZ2XFvLrZ5dniEdAeDephrjgTAODF03ebFD1Wx2L1IyzLc5B0XiGXkktylDUaals/s320/Main%20waveforms%204046.jpg" width="320" /></a></div><br /><div>Here are some screenshots of triangle and sawtooth waves in the Hard Sync function for which this VCO is (rightly) well known. It sounds awesome!</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0__Ii28HRjVvNQfahFEY-w_rG4OiFxZj4B11IJJ-ceLsdm1e6lLDTbMNJyAo-T9qK7ZfZCR90E7CO9kqfVfPSakgMSB0gYOtBItHtNb4uGeW1e6k-daWKC3DfjxrvAITWPQ5aiTsEEP9Sd7yVgLgkYZaTg37eaCp0M4yjYEqLD7KbEe2EQzpmTMtDMoE3/s1599/4046%20triangle%20and%20saw%20hard%20sync-ed.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="978" data-original-width="1599" height="196" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0__Ii28HRjVvNQfahFEY-w_rG4OiFxZj4B11IJJ-ceLsdm1e6lLDTbMNJyAo-T9qK7ZfZCR90E7CO9kqfVfPSakgMSB0gYOtBItHtNb4uGeW1e6k-daWKC3DfjxrvAITWPQ5aiTsEEP9Sd7yVgLgkYZaTg37eaCp0M4yjYEqLD7KbEe2EQzpmTMtDMoE3/s320/4046%20triangle%20and%20saw%20hard%20sync-ed.jpg" width="320" /></a></div><div><br /></div><div>Here's a look at a recently finished project, the 4046 SUPER VCO with the suboscillator from project 69:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7dN8rmUm8rEL5x63qRhO3DTsnh9865NNTDmbm03DZROWGlEiohyphenhyphenLRUwsY8lxoN6WiQHAngIdpda4885GmhdodOOuk18e_a6-yL7aoEf-sOXeZPp20QWZpmEYJ51Zyxpredba_H_R3lLvuUqIP44cwGDF37fIMF8WISLvy9CfGHB0-qhwSwbwzQT06PhB/s3872/X4046%20Super%20VCO-01.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3872" data-original-width="2457" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf7dN8rmUm8rEL5x63qRhO3DTsnh9865NNTDmbm03DZROWGlEiohyphenhyphenLRUwsY8lxoN6WiQHAngIdpda4885GmhdodOOuk18e_a6-yL7aoEf-sOXeZPp20QWZpmEYJ51Zyxpredba_H_R3lLvuUqIP44cwGDF37fIMF8WISLvy9CfGHB0-qhwSwbwzQT06PhB/s320/X4046%20Super%20VCO-01.jpg" width="203" /></a></div><br /><div><br /></div><b><span style="color: red;">DEMO VIDEOS:</span></b><div>Here's a test video showing the VCO in action through the Thomas Henry State Variable filter of the previous project.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/UnxUdqpLAEg" width="320" youtube-src-id="UnxUdqpLAEg"></iframe></div><br /><div>Here's a little test video in which I try the famous Hard Sync function of the VCO. The 555VCO is connected to the Hard Sync input. Sequencer Gate and ADSR out is going into the FM inputs.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dwVLP6e1rMW7PeuZTBkuMrWri2sNlQFk2oJEgJduR1GgWfwdoHp6uC_qDFjKykGv2y1VlqcU5AHSJ9CehDgzg' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here's the video where someone is building this VCO on small pieces of stripboard connected straight to the panel by means of the potmeters.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/sMpikRaV0SY" width="320" youtube-src-id="sMpikRaV0SY"></iframe></div><br /><div><br /></div><div>Okay that's if for this project.</div><div>If you have any questions or remarks please comment below or post them in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group</a> for this website.<br /><div><br /></div></div><div><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-3844039231040397095
title: Synthesizer Build part-58: VCA-1 by THOMAS HENRY.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/04/VCA-1%20for%20stripboard.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>&nbsp;A very good working linear VCA and Mixer using the AS3080 IC. Very easy to build and with a Line Out option too.</p><p>Having built the VCF-1 and the X-4046 VCO designs by Thomas Henry I thought I might as well build the VCA-1 aswell. By coïncidence I needed a new VCA in my DIY synthesizer anyway because the transistor based VCA from way back in the beginning when I started this Modular journey is now starting to act up after working flawlessly for 3 years. It was about time for a new and updated VCA and one with a little more options too. This project is another one from the <a href="https://www.birthofasynth.com/Thomas_Henry/Pages/VCA-1.html" target="_blank">Birth of a Synth</a> website where I got the others from too.</p><p><span style="color: #fcff01;">I built and tested this VCA to run on a dual 12V powersupply so perfect for Eurorack too. It's designed for +/-15V but either voltage will work fine. No component changes needed.</span></p><p>If you're new to DIY synthesizer building and you're not sure about the function of a VCA and what it's for, then please go back to <a href="https://www.eddybergman.com/2019/12/synthesizer-build-part-10-voltage.html" target="_blank">project 10</a> on this website and read the first bit of that article. That will explain it for you. Then come back here and build this one ;)</p><div style="text-align: left;"><span style="color: #fff2cc;">This VCA is not only a Voltage Controlled Amplifier. It's also a 3 channel mixer and it has a Line Out option </span>(all in mono though). I did put in 3 inputs in the layout but I only used one in my own module. I didn't have the room for 3 because I needed this VCA to replace my old one and that one is only 4 CM wide. You could easily add even more channels just by putting in more 100K resistors connected to pin 2 of the TL074, and having your inputs come in through those resistors.</div><div style="text-align: left;">This project was yet an other hole in one. It all worked flawlessly at the first try, just like the X-4046 VCO. I LOVE Thomas Henry designs. They just work so well.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's a look at the finished product on the test bench:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFpuKE-JFXyX80piYmn4Ek9fewPQXxGRneXd8szLCyJGxQIw1cyYkx9ZXkLiW4j_IL-1DZCHVmU6TtcAjL2NUnBoGQ5M0Y0npI87g1mgMUuQSgjSjIl8hm_a4OYpi4bsCHuzyPFBTonlST1IQYnAlJ6G-pWaAY09_upSLwC6hixfQHYM45Gez-GLLzwCwb/s4000/Finished%20module%20undergoing%20testing.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFpuKE-JFXyX80piYmn4Ek9fewPQXxGRneXd8szLCyJGxQIw1cyYkx9ZXkLiW4j_IL-1DZCHVmU6TtcAjL2NUnBoGQ5M0Y0npI87g1mgMUuQSgjSjIl8hm_a4OYpi4bsCHuzyPFBTonlST1IQYnAlJ6G-pWaAY09_upSLwC6hixfQHYM45Gez-GLLzwCwb/s320/Finished%20module%20undergoing%20testing.jpg" width="180" /></a></div><br /><div style="text-align: left;">I made a few changes in the way I'm using this VCA as opposed to how Thomas Henry intended it to be used. TH had the ADSR coming in on an unattenuated input and an extra CV input with attenuation. I turned that around and I have given the ADSR a level control and the extra CV input has no level potmeter. I also put in an extra bi-coloured LED because I used a quad opamp instead of a dual plus a single opamp and just like with the State Variable Filter I had one opamp left over. I connected that to the ADSR input so we have a visual indication that the VCA is receiving an envelope signal and if that signal is positive or negative in Voltage and how strong that signal is, going by the brightness of the LED. Actually a very useful feature to have.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">Here's the schematic I used to make the layout. As mentioned, I made some changes in the type of opamps I used. I also only used one input instead of three. As you can see it's a very simple circuit and it works very well with the AS3080. I used a TL074 for the opamps so the opamp pin numbering on the schematic will be different from the layout. For the diode you can also use a 1N4148 and the small caps C1 and C2 can be ceramic types.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2ALuazt0Qjos9cjQWE1i8Yxpd_aH888eaMk-fhabHrPbDcZAeaoOYsBW_RVqWMYQ-WnMUXnU3-J7lVDzar5-mstODdTnku5zmN3REvjHOxkO-Z-xp3_eShk7JOwXjclSS-_E7ysTYvufx5-phizYSHJtBQF3ikx3lYo1QznGjEdaKKPoxyktK_RQOp1cI/s1156/VCA-1%20by%20TH%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="916" data-original-width="1156" height="254" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2ALuazt0Qjos9cjQWE1i8Yxpd_aH888eaMk-fhabHrPbDcZAeaoOYsBW_RVqWMYQ-WnMUXnU3-J7lVDzar5-mstODdTnku5zmN3REvjHOxkO-Z-xp3_eShk7JOwXjclSS-_E7ysTYvufx5-phizYSHJtBQF3ikx3lYo1QznGjEdaKKPoxyktK_RQOp1cI/s320/VCA-1%20by%20TH%20schematic.JPG" width="320" /></a></div><div><br /></div><span style="color: red;"><b>LAYOUTS:</b></span><div>Below are the layouts I made for this project. As ever they are verified. I used them for my build and it again worked straight away, just like the VCO.&nbsp; Again, the LED was an extra I put in myself and it's not in the schematic. It's fed by an opamp buffer connected to the ADSR input with a Bi-Coloured LED on the output and a 2K4 resistor as current limiter. It's a useful addition.</div><div><br /></div><div>Wiring diagram:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1EfcG1nJxVHTOK6ufgcIR-FRfhLuCZ3N45lDUwxpUCEM51EW0BJ0tF-pDlMEPoWi3NUhDNW4D94f3GXg5vZsZnXto-Z-ftxUThuW9WJbjVGOdDqqXNEXxuagTMfiHp0eOrFVmUG9O9w4y1OWlnZGhHMkkXV442cuRhvTJnnTDsHYqbk5QajYRGjjsXGP7/s8118/VCA-1%20by%20TH%20-%20Wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5302" data-original-width="8118" height="209" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1EfcG1nJxVHTOK6ufgcIR-FRfhLuCZ3N45lDUwxpUCEM51EW0BJ0tF-pDlMEPoWi3NUhDNW4D94f3GXg5vZsZnXto-Z-ftxUThuW9WJbjVGOdDqqXNEXxuagTMfiHp0eOrFVmUG9O9w4y1OWlnZGhHMkkXV442cuRhvTJnnTDsHYqbk5QajYRGjjsXGP7/s320/VCA-1%20by%20TH%20-%20Wiring.jpg" width="320" /></a></div><div><br /></div>Stripboard only view:<div>This layout was small enough to have a few strips left unused which gives up plenty of room to connect some L brackets to mount the stripboard to the faceplate.<br /><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1ulpyq1Qt-LXniSxE8xzahZVLFrO0oX7NJPxDHj9OGIzU3ISHEf1s6x_tGFyUONFhEI862we2NtPtU7rOdHnmLdpKE403vVVPkdst7RBjX2TbKmPe-7xOg5YlsP3e2TdC3XrvaLWwJnIyIQ_c4zO00AP_1Piclkow2BjCYaNfVR8cDlt9EMVpGCW7GQUb/s5000/VCA-1%20by%20TH%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3362" data-original-width="5000" height="215" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1ulpyq1Qt-LXniSxE8xzahZVLFrO0oX7NJPxDHj9OGIzU3ISHEf1s6x_tGFyUONFhEI862we2NtPtU7rOdHnmLdpKE403vVVPkdst7RBjX2TbKmPe-7xOg5YlsP3e2TdC3XrvaLWwJnIyIQ_c4zO00AP_1Piclkow2BjCYaNfVR8cDlt9EMVpGCW7GQUb/s320/VCA-1%20by%20TH%20-%20Stripboard%20only.jpg" width="320" /></a></div><br /><div>Cuts and wirebridges (component side view). I did not bother to make a layout with just the cuts on it because they are easy enough to see on this combined view:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkhxkaLY-shH0t0ehB_mEg33KG6RtbvZjBmQx_bMxEd8wFx34F3Wnyz574bhgFMaj22JA0Nugu_QcxP6IB7ECXJ8ZSky9B14hLIfwKXdKw_tRJe3GRxxzTw-L74E-baw3eLM7GcI0odxvZbR5cBRNvTZXV4g1cc6DpHThDT_amCqGkjpUdBgZt4naSGM7I/s4094/VCA-1%20by%20TH%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3080" data-original-width="4094" height="241" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkhxkaLY-shH0t0ehB_mEg33KG6RtbvZjBmQx_bMxEd8wFx34F3Wnyz574bhgFMaj22JA0Nugu_QcxP6IB7ECXJ8ZSky9B14hLIfwKXdKw_tRJe3GRxxzTw-L74E-baw3eLM7GcI0odxvZbR5cBRNvTZXV4g1cc6DpHThDT_amCqGkjpUdBgZt4naSGM7I/s320/VCA-1%20by%20TH%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><br /><div>And here's the Bill of Materials.&nbsp;</div><div><br /></div><div>You can order AS3080 chips from <a href="https://electricdruid.net/product/as3080e-ota/" target="_blank">Electric Druid</a>.&nbsp;</div><div><br /></div><div>You can also order them from <a href="https://www.thonk.co.uk/shop/alfa-as3080e/" target="_blank">Thonk</a>.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfr5ZpmJ8T-E3RYYMJ17LRFpwTGcOie7-2DfE7gYGiRFAVK8SKKWElAvhZESRMcRK8n_BeMnwDOMpwrw5QgZySgmKZwblhy6p-fRoTgjkGQ0dfit6a5PpiyWin5ByMOpE8tqNZrHHsNso1tF2x-QVofJ2jPRIzvckuRhsJd83xii8C7B1qMTcF4CI-yz6v/s836/VCA-1%20BOM%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="431" data-original-width="836" height="165" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfr5ZpmJ8T-E3RYYMJ17LRFpwTGcOie7-2DfE7gYGiRFAVK8SKKWElAvhZESRMcRK8n_BeMnwDOMpwrw5QgZySgmKZwblhy6p-fRoTgjkGQ0dfit6a5PpiyWin5ByMOpE8tqNZrHHsNso1tF2x-QVofJ2jPRIzvckuRhsJd83xii8C7B1qMTcF4CI-yz6v/s320/VCA-1%20BOM%20Ps.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Testing was pretty straight forward. I connected my scope to the Max. output and put a VCO signal on the input (yellow line) and an LFO signal on the ADSR input (blue line) to serve as envelope signal. The scope showed a beautifully responsive VCA reaction as you can see on the screenshots below.&nbsp;<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBzKEntvE3NM-hSmKbgSw8JFKpH5Kt_AJ49g74oL4mnbtTQqGjXsCtZDz7k82XsDBRuisWoH1PIvHFhkoYZd6icyaRvWszcO0bD-6ERxXQQ-vb5SgZfCJ91xubPVdQ4mOiiFMDlB0ydUxIt4gFS39aBuSEaPed3JcsqcAbH4cCGVUhj4lLPtLN5-rlXClO/s800/VCA%20following%20the%20Envelope.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBzKEntvE3NM-hSmKbgSw8JFKpH5Kt_AJ49g74oL4mnbtTQqGjXsCtZDz7k82XsDBRuisWoH1PIvHFhkoYZd6icyaRvWszcO0bD-6ERxXQQ-vb5SgZfCJ91xubPVdQ4mOiiFMDlB0ydUxIt4gFS39aBuSEaPed3JcsqcAbH4cCGVUhj4lLPtLN5-rlXClO/s320/VCA%20following%20the%20Envelope.jpg" width="320" /></a></div><br /><div>When you turn the INITIAL potmeter past the 1 o'clock position the audio signal will reach its amplitude limit. In that case the VCA will also not shut completely. (The audio will not distort though) You can look at the Initial potmeter as the 'Gain' control on other VCA's. You use it to open the VCA so you have continuous sound without any keys being pressed on the keyboard. The further you turn it clockwise the louder the audio will be.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3IDViNb2nR0wn4t1-TAx-Vu-gT6JROfVTT7lr_NxgLXhF5WXghrUyYDLXKm8pyh7NGkYm48Hp6LBRzqyYPlP8O_x07oRCuKwVoGB2qUSnP76X3cvahrhCS6KXU_llc1joTKbElg7Igledi5okhs0C0eNz2PnRU9IzwkWJzkh9NnKLPR96Xwn2C8lkq49z/s800/VCA%20INITIAL%20tunred%20to%20clipping.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3IDViNb2nR0wn4t1-TAx-Vu-gT6JROfVTT7lr_NxgLXhF5WXghrUyYDLXKm8pyh7NGkYm48Hp6LBRzqyYPlP8O_x07oRCuKwVoGB2qUSnP76X3cvahrhCS6KXU_llc1joTKbElg7Igledi5okhs0C0eNz2PnRU9IzwkWJzkh9NnKLPR96Xwn2C8lkq49z/s320/VCA%20INITIAL%20tunred%20to%20clipping.jpg" width="320" /></a></div><div><br /></div><div>Here you can see the negative voltage rejection on the ADSR input. As soon as the blue line goes through the zero Volt line and higher, the audio will come on. The LED will shine blue when there's a negative voltage presented on the ADSR input and the VCA will just stay closed.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxsWUsJ-DTOERNJ7FndEPIy37TyjqEe63jKKVN15HegpeWw0Um43mPlXIP8o0PevHpqB8dw3KauFIK3LYtmkVMMyRJiAOMGZ8vK_Kma6TXBB28ymC0nBYXWb_9AMQ52tgQcSzuVR1qPpnzJEOMfxJnYtsNhEV14oZ0rxvnNxKHGjlHWl2_cOEfiPFEx6go/s800/DS1Z_QuickPrint1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxsWUsJ-DTOERNJ7FndEPIy37TyjqEe63jKKVN15HegpeWw0Um43mPlXIP8o0PevHpqB8dw3KauFIK3LYtmkVMMyRJiAOMGZ8vK_Kma6TXBB28ymC0nBYXWb_9AMQ52tgQcSzuVR1qPpnzJEOMfxJnYtsNhEV14oZ0rxvnNxKHGjlHWl2_cOEfiPFEx6go/s320/DS1Z_QuickPrint1.jpg" width="320" /></a></div><br /><div><br /></div><div><b><span style="color: red;">CALIBRATING THE VCA:</span></b></div><div>This is simple. There's only one trimmer and you use it to trim away any DC offset on the audio output. What you do is you connect an oscilloscope to the Max output. Set the AC/DC switch to DC. Then you put an audio signal on the input and an LFO signal on the ADSR input, like the screenshot's above. Then you turn the trimmer until the signal is centered around the zero Volt line. In other words, the zero Volt line goes straight through the middle.&nbsp;</div><div>That's all.</div><div><span style="color: #fcff01;">TIP:</span> Instead of an envelope signal opening and closing the VCA, try using an audio signal. This VCA can work very fast and if you use an audio signal you get a sort of ring-modulation in combination with the signal you have on the audio input. Try experimenting with this.</div><div><br /></div><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures of the finished module:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVoCYJCHxxHersdAYnBQDHNf5K3XL315HMQeQs_a3Rqal-YIVHEgsOGWHxByVqzsQyvUP4-jnL9u3KI8idZtNE_VAIeqEPBENsDWbHJEduOJSsicUQdmD0XIFP5Ej1Rs9j09taKntzZDvTnXC9nbx3A7bPug_fSWFgsoiaNLbs3Eeug_Z7gzpvcnt5-Eul/s4000/VCA%20closeip%20of%20the%20stripboard.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVoCYJCHxxHersdAYnBQDHNf5K3XL315HMQeQs_a3Rqal-YIVHEgsOGWHxByVqzsQyvUP4-jnL9u3KI8idZtNE_VAIeqEPBENsDWbHJEduOJSsicUQdmD0XIFP5Ej1Rs9j09taKntzZDvTnXC9nbx3A7bPug_fSWFgsoiaNLbs3Eeug_Z7gzpvcnt5-Eul/s320/VCA%20closeip%20of%20the%20stripboard.jpg" width="180" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnAyZWUEPSgHKjMyg-ysMLbbQJIC5La-COAxX1xqjXQoRSlE9f_o7xOzl4osUsEHZUvGejeT8I2ecnaKnMLX3n61Ru0GxC3e3SBQaJedR7XsbKC1miMOmH1wVoRxg4COxJJDHASkTZOBh4_g0yzsO7x9SCJph90TagR6uXb6odwmnh-it6-Pn2zMjrVdBA/s4000/VCA%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnAyZWUEPSgHKjMyg-ysMLbbQJIC5La-COAxX1xqjXQoRSlE9f_o7xOzl4osUsEHZUvGejeT8I2ecnaKnMLX3n61Ru0GxC3e3SBQaJedR7XsbKC1miMOmH1wVoRxg4COxJJDHASkTZOBh4_g0yzsO7x9SCJph90TagR6uXb6odwmnh-it6-Pn2zMjrVdBA/s320/VCA%20finished.jpg" width="180" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWzbSBFYseFhwpWLSN7WOe3WTGupk4FvVJPlpCI6IX_5Jp_9Ft2KJcPSl0bfxF7Xv5sdKabyyGfyZ_u5K5yQ-_sKHEmzna5IRY9rh6qYixGQTnqE2Iq0TosmVoCx9CNyVtYWC3TwgFmI3HIgT7PSjbHoKBayUaSSF6SAC50IWmkILk97HtQ2yznt8sKTbG/s4000/VCA%20in%20place%20in%20the%20synth.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWzbSBFYseFhwpWLSN7WOe3WTGupk4FvVJPlpCI6IX_5Jp_9Ft2KJcPSl0bfxF7Xv5sdKabyyGfyZ_u5K5yQ-_sKHEmzna5IRY9rh6qYixGQTnqE2Iq0TosmVoCx9CNyVtYWC3TwgFmI3HIgT7PSjbHoKBayUaSSF6SAC50IWmkILk97HtQ2yznt8sKTbG/s320/VCA%20in%20place%20in%20the%20synth.jpg" width="180" /></a></div><br /><div>Finally here's a link I found for an article dealing with different ways to add voltage control to circuits that don't have it. It really has nothing to do with this VCA project but I thought I'd put the link in this article so I can find it again should I need to.</div><div><a href="https://northcoastsynthesis.com/news/voltage-control-modifications/" target="_blank">--- click here ---</a></div><div><br /></div><div>So that's it for now. Three in a row this month and three very good Thomas Henry projects for you to sink your teeth in.</div><div>If you have any questions or remarks please comment below or in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group</a> for this website.</div></div><div><br /></div><div><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-4926640371775742506
title: Synthesizer Build part-59: BASS++ DRUMVOICE by THOMAS HENRY.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/04/Bassplusplus.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>Finally a new drum related project and this is a really good one. This circuit creates all sorts of percussive sounds from Bass drum and Tom-Toms to Woodblock and a lot in between.&nbsp;</p><div style="text-align: left;">Once again a Thomas Henry project. They're just so good and I wanted to build a drum related module for a long time to expand on the 808 Kickdrum from Juanito Moore. This is a relatively simple circuit to produce such a wide variety of drum sounds.&nbsp;</div><div style="text-align: left;">Here's the schematic I used to make the stripboard layout:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAdpsTRPHAWvm_wv9-oGr8KK4RYUvwpVhvAA6S38OfoH9mYw4SEDcx-PVHisZxXeb2BTAOa_2OpaPfw9U-bCzWyDGJNkj3KZrIDdHBkI0frQk3Vr2ZAlALJCYEx7OUnYkCAa_DvaC2O2DwOm2J9dpY_2uhVDcsinR8Ch0crsfDbK-w9vLmMCBTDx05XrjH/s943/Thomas%20Henry%20Bass%20plus%20plus%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="730" data-original-width="943" height="248" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAdpsTRPHAWvm_wv9-oGr8KK4RYUvwpVhvAA6S38OfoH9mYw4SEDcx-PVHisZxXeb2BTAOa_2OpaPfw9U-bCzWyDGJNkj3KZrIDdHBkI0frQk3Vr2ZAlALJCYEx7OUnYkCAa_DvaC2O2DwOm2J9dpY_2uhVDcsinR8Ch0crsfDbK-w9vLmMCBTDx05XrjH/s320/Thomas%20Henry%20Bass%20plus%20plus%20schematic.JPG" width="320" /></a></div><br /><div style="text-align: left;">Just two IC's and 4 transistors. The core of the circuit consists of a VCO built up from the first of the two OTA opamps in the LM13700. This is called the Shell VCO. The VCO's pitch is influenced by the little Envelope Generator consisting of the 2,2µF capacitor and the Decay potmeter fed from IC-2a. This opamp takes the Trigger pulse and with the Sensitivity control, which is an offset control really, turns it into a useable Envelope signal. The VCO also has it's own manual pitch control and there's an external CV input with a level control (Range) and this is where the real magic lays because if you input a VCO signal into this CV input all sorts of weird sounds result. The VCO output goes through the second OTA which functions as a VCA with a buffered output. There are DC blocking capacitors (2,2µF) to get rid of any offset voltages.</div><div style="text-align: left;">Then there's an Impact section which provides the beat, so to speak. It creates the initial hit of the stick on the drum which you can control in tone and intensity. This is fed from the same trigger pulse as the Envelope Generator.</div><div style="text-align: left;">I did not have any 2,2µF electrolytic caps in stock so I used 3,3µF or 4,7µF caps in those places where they are used as blocking capacitors. The value of those isn't that critical. However C11 is the capacitor that determins the Decay length and for that I used two 1µF caps in parallel. With the wide tolerances they have that came to 2,3µF when I measured them together so that was ideal.&nbsp;</div><div style="text-align: left;">C2 is an other critical capacitor. It determins the frequency range of the VCO so keep to the indicated value for that one. You can make that cap switchable with other values to change the base frequency of the VCO. I leave that up to you.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">If you want to know more or you want a more detailed explanation of the circuit then I urge you to read the original article on the <a href="https://www.birthofasynth.com/Thomas_Henry/Pages/Bass_Plus.html" target="_blank">Birth of a Synth website</a>.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">MODIFICATIONS:</span></b></div><div style="text-align: left;">Because it is such a simple circuit people have been modifying this circuit in all sorts of ways. Some of these modifications you can check out via this link to the <a href="https://electro-music.com/forum/post-339776.html" target="_blank">electro music forum</a>:</div><div style="text-align: left;">One thing you can do is add an extra socket so you can input external envelope signals. Have it normalled to the built in E.G. and then break that connection when a patch cable is inserted.&nbsp; I think a good place to insert that signal would be between the output of the opamp (pin 1 of the TL072) and the junction that connects to all the diodes.&nbsp;</div><div style="text-align: left;">An other thing is to add a built-in noise generator by means of a transistor with the collector-leg cut off. This would be handy for snare like sounds.</div><div style="text-align: left;">You can also add a switch to choose between different values of timing cap (C2) to be able to change the frequency range of the VCO.</div><div style="text-align: left;">With the circuit being this simple it will be easy to add to it and make it your own. I will leave that up to the individual builder. This article just deals with the original version.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Below is the series of layouts I used. They are verified as always and this project was yet an other hole in one. It worked straight away, no trouble shooting required. I kept the layout small enough to fit behind a Eurorack panel. Just 24 strips with a width of 41 holes.</div><div style="text-align: left;">Wiring diagram:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4tUACJk_vEYPifDYDK-i8t8HE712iIf4iLV5QATqFpsR9cxmULnM2eaKi_qCqg-7gfCK5ulswtKSx9gMoFbj8AvYH-3AYOOOmb9eTtOqytTG7-lFL3NoBDzxDTEaGvCFomZqQkDLQ2HlO8JXOQNxYUOTSyQ976_89XYvFRkWRzaKWttZpON7ppAOk2dx_/s9156/TH%20Bass%20++%20-%20Wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5389" data-original-width="9156" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4tUACJk_vEYPifDYDK-i8t8HE712iIf4iLV5QATqFpsR9cxmULnM2eaKi_qCqg-7gfCK5ulswtKSx9gMoFbj8AvYH-3AYOOOmb9eTtOqytTG7-lFL3NoBDzxDTEaGvCFomZqQkDLQ2HlO8JXOQNxYUOTSyQ976_89XYvFRkWRzaKWttZpON7ppAOk2dx_/s320/TH%20Bass%20++%20-%20Wiring.jpg" width="320" /></a></div><div><br /></div>Here's the stripboard only view:<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdK7vVr_glbUVU-N16xaxfhyEKqzng6JRkt7JQfu-jDqvMmJRVOPRaOyad7z6IJ6StcwSvw-o6tXdpTdQ1RTBiCOI17JvdWdbFmplc1fapdF7SjTgSjRvUYEaAi1ascUQhRzKqGpOhgKyYOaSgpGyg61vWyK1qGvaK14JfZma3xPnRhhqpf990QN8gWlis/s6000/TH%20Bass%20++%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3671" data-original-width="6000" height="196" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdK7vVr_glbUVU-N16xaxfhyEKqzng6JRkt7JQfu-jDqvMmJRVOPRaOyad7z6IJ6StcwSvw-o6tXdpTdQ1RTBiCOI17JvdWdbFmplc1fapdF7SjTgSjRvUYEaAi1ascUQhRzKqGpOhgKyYOaSgpGyg61vWyK1qGvaK14JfZma3xPnRhhqpf990QN8gWlis/s320/TH%20Bass%20++%20-%20Stripboard%20only.jpg" width="320" /></a></div><div><br /></div>The cuts and wirebridges:<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNoEdvKiJcNOo206se8Dvv9Fw4cm2YxqwWh_jHT-ic6J2Z-MQniSl2JnSs0a1YHQQrweoXpuSvYA_jS5b-wnsmPFDDDHwr-qlH9ST3NaxFRp31iqq_6jNhrudqk3-PoKr3J5gglIk39KPBKz63Zv86K1VezZpAIJDaAaLim61fInGo0RgOYxtrBYQO0UXT/s4677/TH%20Bass%20++%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4677" height="205" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNoEdvKiJcNOo206se8Dvv9Fw4cm2YxqwWh_jHT-ic6J2Z-MQniSl2JnSs0a1YHQQrweoXpuSvYA_jS5b-wnsmPFDDDHwr-qlH9ST3NaxFRp31iqq_6jNhrudqk3-PoKr3J5gglIk39KPBKz63Zv86K1VezZpAIJDaAaLim61fInGo0RgOYxtrBYQO0UXT/s320/TH%20Bass%20++%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><br /><div>And finally the cuts only view. Seen from the component side.&nbsp;</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVKJQdueDsqtiI3LuLhaDb9OtTBkfBV1uCvh5yrFOC2FRmEVq3-_5QS3LEPTnQmKCAfE9TVAvLpzwUrCajIfa7W4xZa-Zo7cVV_UyjmsYCVn5icoe1X8rPWTWfCFyluy_QQXDwc2rOIGcpnfTQzDqcnoXz57uT4C9oilj3L9HzURGH4riYymzCzf9-JK4C/s4760/TH%20Bass%20++%20cuts.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3052" data-original-width="4760" height="205" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVKJQdueDsqtiI3LuLhaDb9OtTBkfBV1uCvh5yrFOC2FRmEVq3-_5QS3LEPTnQmKCAfE9TVAvLpzwUrCajIfa7W4xZa-Zo7cVV_UyjmsYCVn5icoe1X8rPWTWfCFyluy_QQXDwc2rOIGcpnfTQzDqcnoXz57uT4C9oilj3L9HzURGH4riYymzCzf9-JK4C/s320/TH%20Bass%20++%20cuts.jpg" width="320" /></a></div><div><br /></div><div>Mark the cuts on the component side with a waterproof Sharpie or Edding pen and then stick a pin through the marked holes and mark them again on the copper side. Then cut the copper at the marked positions. Be very accurate here. There's not much room for errors.</div><div><br /></div><div>Here's the Bill of Materials:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLlCfyTRfIW27v8IFgSkokkkFmEd3BCmanhpIh5YT9J4r2g9kgybXLNSsG7qvyRLfqGzsv4NRpSMsNfxDUsPVOA-N9uDCgUJUFeMXQH_JRR0469fy1MFeCyOuCPifFt7tKWV6w8KpLUq0Nfru1sRtbsLSequELtEXBxPalrj2qUWMllN_YBnwtvB4Bi_qr/s930/TH%20Bass++%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="581" data-original-width="930" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLlCfyTRfIW27v8IFgSkokkkFmEd3BCmanhpIh5YT9J4r2g9kgybXLNSsG7qvyRLfqGzsv4NRpSMsNfxDUsPVOA-N9uDCgUJUFeMXQH_JRR0469fy1MFeCyOuCPifFt7tKWV6w8KpLUq0Nfru1sRtbsLSequELtEXBxPalrj2qUWMllN_YBnwtvB4Bi_qr/s320/TH%20Bass++%20BOM.JPG" width="320" /></a></div><br /><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures from the build process:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiEFHCjA_xFLxGY1EGZsdY3NqfJzOWYmRSl_tYblJffRlxkGrky-Wonlu7i3yXKYr-SEm7xnvvEv9dCNY85_6kxeWZogUY9iCfN_gjpWKT9UgzbbTIdprspW9MNlK_3qs43VeO628F9lGdqvrvM4IV3NgiUTb39q81e_JQRxAy1rCLYD5WM34XMt3Uvp-U/s3280/02a%20Finished%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="3280" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiEFHCjA_xFLxGY1EGZsdY3NqfJzOWYmRSl_tYblJffRlxkGrky-Wonlu7i3yXKYr-SEm7xnvvEv9dCNY85_6kxeWZogUY9iCfN_gjpWKT9UgzbbTIdprspW9MNlK_3qs43VeO628F9lGdqvrvM4IV3NgiUTb39q81e_JQRxAy1rCLYD5WM34XMt3Uvp-U/s320/02a%20Finished%20wirebridges.jpg" width="320" /></a></div><br /><div>The finished stripboard:<br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdBplenKdh7Ajn6c0y5k6kTi6nsZNSS58Dourdyeb2wFjXAs9YBUKDLppU0s2YoRzU3AT9yu_NxEqK4rYqqwAps-boEeYfXLK3yLJi5_ThB28hJZP2bc7jPO7JP5gRlzC8cGvl96_-KOsAP5_GLoILnQnOvLmjTEZYszri8OenAZ9pjWcRswiEUPDyxNQZ/s3268/03a%20Finished%20stripboard.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2084" data-original-width="3268" height="204" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdBplenKdh7Ajn6c0y5k6kTi6nsZNSS58Dourdyeb2wFjXAs9YBUKDLppU0s2YoRzU3AT9yu_NxEqK4rYqqwAps-boEeYfXLK3yLJi5_ThB28hJZP2bc7jPO7JP5gRlzC8cGvl96_-KOsAP5_GLoILnQnOvLmjTEZYszri8OenAZ9pjWcRswiEUPDyxNQZ/s320/03a%20Finished%20stripboard.jpg" width="320" /></a></div><div><br /></div><div>Because this circuit is a bit difficult to understand and therefore the function of the 9 different knobs is also not easy to understand I decided to make a faceplate with a sort of block diagram on it so I could show which knob controls which part of the circuit. This would make the faceplate a lot bigger but it would also make the user understand which part of the circuit he was influencing.</div><div>It was not easy to design a flowchart or block diagram that was simple enough but also true to the functioning of the circuit and it took me about 4 drafts before I was happy with the design.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL2fcBaLtmC9tucTBoKxpIa8QncK7k4QoOiFXmCLLklVUWyP2OPBfPI7LzbnGSH0esj1Fh5JDn9l1ZPF6AIx_i4eIBLvkS_-6s83hkdczwphjF2iwmxe1cWghdXc4JqykqZmCevsDgpjvoootjeYsAbQB-jyI2r6JHVjNTzP5DANwEPlg9JBGOFliZPz8M/s4000/04a%20Faceplate%20design%20process.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL2fcBaLtmC9tucTBoKxpIa8QncK7k4QoOiFXmCLLklVUWyP2OPBfPI7LzbnGSH0esj1Fh5JDn9l1ZPF6AIx_i4eIBLvkS_-6s83hkdczwphjF2iwmxe1cWghdXc4JqykqZmCevsDgpjvoootjeYsAbQB-jyI2r6JHVjNTzP5DANwEPlg9JBGOFliZPz8M/s320/04a%20Faceplate%20design%20process.jpg" width="320" /></a></div><br /><div>Here's the resulting faceplate:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJt_sKhpQR1fhK8gAbZLW1Y9pbkccrBtJVy5kdV6MWKEtj73RrpSv65yaZPo6Odmm1eApwHTZRNuc3W3Ofb9Cw7rcEn2PbfSy61My_vkAXZJZpNb9T4-xBKc6NRbbVdJPVaRVbnFydW7gmoEFIDAWcAwDav7K9TF4NRjYVoeBAg_so4v-s-6fVsdtkGSs1/s4000/05%20Faceplate%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJt_sKhpQR1fhK8gAbZLW1Y9pbkccrBtJVy5kdV6MWKEtj73RrpSv65yaZPo6Odmm1eApwHTZRNuc3W3Ofb9Cw7rcEn2PbfSy61My_vkAXZJZpNb9T4-xBKc6NRbbVdJPVaRVbnFydW7gmoEFIDAWcAwDav7K9TF4NRjYVoeBAg_so4v-s-6fVsdtkGSs1/s320/05%20Faceplate%20finished.jpg" width="180" /></a></div><div><br /></div><div>Everything in place ready to be wired up:</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWcL8jJhPgEi0g80XE_BGmaxJ0oNnb8FYef9zTg4v03Ka-Nzh73bsfKqVZ6N5RL_uPzAbbmEky_qR4pyoJEJheHG6AQxCwFdCSL8zINJlEcaige3KtKJ0Ha8QFHG5gpQ6y1bwvMpoUoiGYjH0HRJnilBXGFSN4dS19f0TWNHWPx1tWTiLAZOsx9sg6enJj/s4000/06%20Module%20before%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWcL8jJhPgEi0g80XE_BGmaxJ0oNnb8FYef9zTg4v03Ka-Nzh73bsfKqVZ6N5RL_uPzAbbmEky_qR4pyoJEJheHG6AQxCwFdCSL8zINJlEcaige3KtKJ0Ha8QFHG5gpQ6y1bwvMpoUoiGYjH0HRJnilBXGFSN4dS19f0TWNHWPx1tWTiLAZOsx9sg6enJj/s320/06%20Module%20before%20wiring.jpg" width="320" /></a></div><br /><div>And here's the final result. Each section of the circuit has its own colour knobs. The trigger pulse is visible through the yellow LED inside the triangle:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ5Y26KixNR26uTCqvxuCd5IWVdYbpwDjSlJ7k1VI_Q3jer_Bqo8rvbM99ayj8IYTtnzHHkTrv5BonkEW1cYlYvThBY0plS9SDBmSHNE7H098bC4HPGqh34nEeHu26CJfqenwjGkFMBEOyJsxKXDO4ms2Pb5bThvfVeYtsqbb22C8pPIeErSuToPf2z0dS/s4000/07%20Front%20view%20finished%20module.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ5Y26KixNR26uTCqvxuCd5IWVdYbpwDjSlJ7k1VI_Q3jer_Bqo8rvbM99ayj8IYTtnzHHkTrv5BonkEW1cYlYvThBY0plS9SDBmSHNE7H098bC4HPGqh34nEeHu26CJfqenwjGkFMBEOyJsxKXDO4ms2Pb5bThvfVeYtsqbb22C8pPIeErSuToPf2z0dS/s320/07%20Front%20view%20finished%20module.jpg" width="180" /></a></div><br /><div><b><span style="color: red;">VIDEO DEMO:</span></b></div><div>Here's a little video of me trying the module out for the first time. Don't expect too much from this. I was just fooling around with it. I had a pulse wave on the Trigger input and a sawtooth from my VCO (which was connected to the sequencer) going into the CV input.</div><div>I recorded the audio of this video separately with a Zoom H8 to get the best bass tones which my phone would never pick up.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dwFjEnBlpB9U0wR-GIv1pqR-SBy3gXO5f7VYt8cfEaKHvHJC7-vioxQoG1vntjZDa1bCDuguLOdXSqS_XAvFA' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div>This module can replicate that late 70's 'Peewww peeewww sound made famous by Kelly Marie in her song 'It feels like I'm in love' . Remember that one? (LOL)</div><div>It's capable of much more than can be seen in this demo video, if you go to the <a href="https://www.birthofasynth.com/Thomas_Henry/Pages/Bass_Plus.html" target="_blank">'Birth of a Synth' website Bass++ article</a> and listen to the sound sample posted there, you can hear what this module is really capable of.<br /><div style="text-align: left;"><br /></div></div></div><div style="text-align: left;">Okay that's an other one done and again a Thomas Henry design. They are just so good. They always deliver.</div><div style="text-align: left;">If you have any questions or remarks about this project then please put them in the comments below or post on the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group for this website</a>.</div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-1324354886656253245
title: Synthesizer Extra's No.5: PROFESSIONAL LOOKING PANELS using WATERSLIDE PAPER.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/10/waterslide%20decals.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">&nbsp;An easy way to make your panels look really professional.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I've been doing this hobby for over 4 years now and all that time I always used black powdercoated aluminium to make my panels from and I always use a white acryllic pen to write all the labeling etc.&nbsp;</div><div style="text-align: left;">It works fine but it doesn't look very professional.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">For a long time I've seen people using waterslide decals to apply to their panels and it looks very slick. I wanted to try that myself so I ordered some "Water-based ink jet water transfer paper". That's what is says on the label. You can order this from AliExpress or your preferred webshop. If you Google it you'll find lots of sellers.</div><div style="text-align: left;">Make sure, if you use an inkjet printer like I do, to order transfer paper suitable for inkjet printers. It must say inkjet on the package and it must be transparent. If you use a laser printer then there's special transfer paper for that too.</div><div style="text-align: left;">There is also white transfer paper available and i just took delivery of that too. I want to experiment with black backgrounds.</div><div style="text-align: left;"><span style="color: #fff2cc;">IF THIS IS YOUR FIRST TIME WORKING WITH WATERSLIDE PAPER, MAKE SOME TEST PIECES AND TRY TO APPLY THAT TO A SURFACE FIRST!</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: red;"><b>First step: Design your panel layout.</b></span></div><div style="text-align: left;">I do all my designs in Photoshop. I like working with Photoshop because you can work with layers and the centimeter markings on the side are very accurate to how it will roll out of the printer.</div><div style="text-align: left;">There are also special layout design programs on the internet, like '<a href="https://www.frontpanelexpress.com/front-panel-designer" target="_blank">Schaeffer AG Front Panel Designer</a>' which you can download for free.&nbsp; There is also a free program called Inkscape which should work very well too. You can <a href="https://inkscape.en.softonic.com/" target="_blank">download that by clicking here</a>.&nbsp;</div><div style="text-align: left;">I got the following link from a comment on the Facebook group. Also a faceplate designer: <a href="https://synthpanels.design/?fbclid=IwY2xjawGr2WVleHRuA2FlbQIxMAABHdavIlLrMGFqZkagFZgGV3EVTwPCWEZhGHI8XnCoY2LIZniELMVSx6aRJA_aem_PKHaHByt7osb_Rf1B1j8Vw#" target="_blank">--- CLICK HERE ---</a></div><div style="text-align: left;">I have not worked with these yet although I intend to try them out soon.</div><div style="text-align: left;">You can find decal designs on the internet or make your own. Make sure you draw in dots for the places where you need to drill holes in the panel so you know where to drill them.</div><div style="text-align: left;">One tip I can give you is to make your panel design just a little bit smaller than the actual panel. Just a millimeter on the sides and have it start and end inbetween the holes in the panel where you screw it into the synthesizer case. That way the lacquer you apply later will seal those edges and prevent them from coming loose, which can happen if they are exactly on the edge of the panel.&nbsp;</div><div style="text-align: left;">Here's a picture to illustrate that point. You'll see in the light reflection on the top how the lacquer forms a protective layer over the edge which runs just under the mounting hole:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhb0QcPdydqvci0ZP2RTrGx4vjqRhg1u5EZGWjrwKLDo96so6jCFq0zXDRlWR-rkWUbEuhr-K3tO4mMK8lDl4w4b4Ni97VolX4GE4IUsXkfSbWJQPvkgljDjE6xNnEBQOQh1ZMsTW9GtjCrY5duMxo8LwhH5MMBNtd0vElC_wL9c9w34uT9CbRAK0cWPyUU/s4000/20241015_205420Wavehaper%20testing-01.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhb0QcPdydqvci0ZP2RTrGx4vjqRhg1u5EZGWjrwKLDo96so6jCFq0zXDRlWR-rkWUbEuhr-K3tO4mMK8lDl4w4b4Ni97VolX4GE4IUsXkfSbWJQPvkgljDjE6xNnEBQOQh1ZMsTW9GtjCrY5duMxo8LwhH5MMBNtd0vElC_wL9c9w34uT9CbRAK0cWPyUU/s320/20241015_205420Wavehaper%20testing-01.jpg" width="180" /></a></div><br /><div style="text-align: left;">Btw, that panel had a typo in it, the plus signs should have been multiply signs but I still used it because it came out so well. This was the second panel I ever made using this method and it went perfectly.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here is my first design for the Digisound-80 VCO, made in Photoshop and printed on A4 paper. (feel free to use it if you want):</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjecFsRErdIonxy2d0fqQ_IK1XBY94ANWkS7GnhP8EhxWYR8AcEI5BRH7Q8f-bI90clieUcfmzJnczApGkhPMCtxGaiKh-tfmBQCc4E8fEumArqBerN4E2MZsO3Veen79qCLdgOxX4Xjf1pIAg8ZtCjM_d_oGghlcbcZgJrl0hEGUvBB_NzYH_QV333hCHA/s3496/AS3340%20VCO%20panel%20design-V2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3496" data-original-width="2480" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjecFsRErdIonxy2d0fqQ_IK1XBY94ANWkS7GnhP8EhxWYR8AcEI5BRH7Q8f-bI90clieUcfmzJnczApGkhPMCtxGaiKh-tfmBQCc4E8fEumArqBerN4E2MZsO3Veen79qCLdgOxX4Xjf1pIAg8ZtCjM_d_oGghlcbcZgJrl0hEGUvBB_NzYH_QV333hCHA/s320/AS3340%20VCO%20panel%20design-V2.jpg" width="227" /></a></div><br /><div style="text-align: left;">I drew in the Octaves and Freq Fine control markings after measuring on the VCO where they should go so they actually indicate where the different octaves are and on the fine control where the notes are within the octave. However I used a 2M7 resistor for the fine control, not a 3M3 as recommended so my fine control covers a little more than the normal half octave. Note the dots that indicate where to drill the holes for the potmeters and sockets.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Step two: Prepare your waterslide paper.</span></b></div><div style="text-align: left;">Now print your design onto the waterslide paper. <span style="color: #fff2cc;">Make sure you print out as many of your designs as you can fit on one sheet of paper. Copy and paste them next to eachother. You can only use an A4 size paper once so if you make a mistake you will have a few others as back-ups.&nbsp;</span>It's a shame to have to throw away 2/3rds of your waterslide paper unused.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's how I printed the design of the envelope follower panel. Four on one A-4 piece of waterslide paper:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEiairXDYj2TBpPKUFe2WmhCYHm_7pZSX8VMPJEBjgGtLfNNpm0mQRQfCXLraKUxes2vFdLlqQAixA8ozkPNhZbV9_UavHdjhhGjl5NmriZJShjfNvH1-siJ9CRfEGI_7P6V06G3CLjaE5RYQZoxAZ7xoyw3U40hu85U2EmhDopchKOyuZ0omOUP0StAL4/s3496/Envelope%20Follower%20panel%20ready.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3496" data-original-width="2480" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEiairXDYj2TBpPKUFe2WmhCYHm_7pZSX8VMPJEBjgGtLfNNpm0mQRQfCXLraKUxes2vFdLlqQAixA8ozkPNhZbV9_UavHdjhhGjl5NmriZJShjfNvH1-siJ9CRfEGI_7P6V06G3CLjaE5RYQZoxAZ7xoyw3U40hu85U2EmhDopchKOyuZ0omOUP0StAL4/s320/Envelope%20Follower%20panel%20ready.jpg" width="227" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Now cut the design out with scissors. I use one of those paper cutters with a rotating knife on a rails that you can put the paper under. It guarantees a straight cut. Round off the edges a little with scissors. Make sure you cut it a bit smaller than the panel size so that the waterslide paper doesn't sit right at the edge of your panel. It will come loose over time if that happens.</div><div style="text-align: left;">Now apply a few thin coats of clear acryllic lacquer onto the paper. You can of course also do this first before you cut it out. Make sure there's no dust or hairs on the paper and let it dry a few hours and apply a second coat. These coats not only protect the ink they also make the paper stronger when applying it to the panel.&nbsp;</div><div style="text-align: left;">If you use a laserprinter that uses toner then you don't have to apply the lacquer. However inkjet prints are not waterproof so they must be protected with lacquer. Make sure it is well dried before moving on.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div><span style="color: red;"><b>Step three: Prepare the panel.</b></span></div><div>Take the design you made and print it out again but this time on a normal piece of paper. We are going to use this as a drill guide, to drill the holes in the right place.&nbsp;</div><div>Take your panel material, in my case white powdercoated aluminium, and apply the printed design to the protection layer of the panel with doublesided tape. You can use other methodes but I find this the easiest to do. Usually the panel material will have a protection layer against scratching, if it doesn't have that just put some paper tape on it first. The kind you use to tape off edges when you paint a door for instance. Stick your design to the panel and make sure it can't move.</div><div>Now use a very thin drill to make the first pilot holes. I used a 3,3mm drill the first time but that was too big and I couldn't place the drill accurately enough which caused me some problems when I put in the potmeters. 1,5mm will be better. So make sure you drill very accurately. Then drill the holes to the right size and take off the paper/protection layer. Make sure you de-burr the holes you just drilled. There must be no upstanding edges around the holes because that will cause air pockets under the waterslide paper or it will tear the design when you apply it to the panel.</div></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Step four: Apply the waterslide paper to the panel.</span></b></div><div style="text-align: left;">Now take a nice big bowl and fill it 2/3rds with slightly luke warm water. Put one drop of washing up liquid in in the bowl and then add the water. This decreases the water surface tension. If the water has gone all bubbly, just scoop out most of the bubbles with your hand so you can see what you're doing.&nbsp;</div><div style="text-align: left;">Put the waterslide paper into the bowl. It will immediately curl up. Carefully roll it out with your fingers under water and make sure it is completely in contact with the water. The paper will straighten out. Keep it under water for about 30 to 35 seconds and then take it out.</div><div style="text-align: left;"><div><span style="color: #fcff01;">MAKE SURE the image doesn't come off while it is still in the water!!</span>&nbsp;Or all the glue will wash off. That's why I say&nbsp;<span style="color: #fff2cc;">30 to 35 seconds in the water is about right.</span></div><div>Put a little water on the panel with your fingers to wetten it a little. Make sure the panel has been de-greased and free of fingerprints. (A little alcohol does wonders in cleaning the surface beforehand).</div></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Now take out the waterslide paper and place it over the panel. Grip it carefully with your fingers on the top side of the panel and then rub the bottom side between your fingers in such a way that the bottom layer slides out from under the image layer. Your thumb stays in place while your fingers slide the backpaper downwards. If this doesn't go smoothly, the paper needs a little more time to absorb the water and liquify the glue. Be patient and careful.</div><div style="text-align: left;">Slide the back layer down from under the image layer. It is important that you don't move the waterslide paper too much once it is applied to the panel because this will impact on the stickiness of the paper. The slippery stuff underneath the image layer is actually the glue so you need to make sure this is not washed away by too much movement.</div><div style="text-align: left;">There are special 'decal setting solutions' available for purchase, that will cure the layer and make for a good bonding between panel and image layer. I don't own any of that myself but I might try this later, however you don't really need it.&nbsp;</div><div style="text-align: left;">Now once the waterslide paper is in the right place, carefully squeeze out the water underneath the waterslide image by using the backpaper as a squeegee. Carefully move it over the image layer and squeeze out any water underneath. (Use the slippery side.) Be careful not to crease or tear it! This takes a bit of practise but it doesn't have to be perfect. The image layer may still look a bit rippled but that will disappear when it dries up. Make sure there are no folds though. When the water has been squeezed from under the paper, you can use a fine cloth to dry the surface of most of the water. Be very careful though. If you don't trust yourself, leave the water on top. It will evaporate anyway. I put it on the central heating in my room and it was dry within an hour.&nbsp;</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's how it looks freshly applied after I went over it with the backpaper to squeeze out most of the water. It's still very wet and a bit wrinkly but that doesn't matter:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwbVe82LudBAB9o2TfOAi8Md77rBkJou_BJ-dRoO4dltSpsdRkIkeiQmzPzexkP-cHlHYLSfym1UiTQEVEHmx7V7LDLp7ncgkrwedJFyNt_179tSvQ_fBweg5f9NtVmdc1AB4JOwomZXJNrz7oFfNCl9BtgY4VsjMplNJ9djOo5j2UHsTzoOTdbUPLz2oc/s4000/20241202_155505.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwbVe82LudBAB9o2TfOAi8Md77rBkJou_BJ-dRoO4dltSpsdRkIkeiQmzPzexkP-cHlHYLSfym1UiTQEVEHmx7V7LDLp7ncgkrwedJFyNt_179tSvQ_fBweg5f9NtVmdc1AB4JOwomZXJNrz7oFfNCl9BtgY4VsjMplNJ9djOo5j2UHsTzoOTdbUPLz2oc/s320/20241202_155505.jpg" width="320" /></a></div><br /><div style="text-align: left;">After an hour on the central heating the layer has pulled itself tight on the surface and it's completely dry:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRpoyhyphenhyphen_viawzVlxiT2uCx_p9nMXJFGAkSlwr4eqBudVLhJO6Sxp-4tQGcongNRG5km48gUmbKaXkR6ebEPYCHofImX0jYltF51uWW__7Pmb6PmZnut28cSNl4t-5tY6bKtZW2xhSZMvfh3XgC-C9SkMZ6fKyWXKsUcntde4fiihgayFV6LyC3eCaVSuIf/s4000/20241202_165012.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRpoyhyphenhyphen_viawzVlxiT2uCx_p9nMXJFGAkSlwr4eqBudVLhJO6Sxp-4tQGcongNRG5km48gUmbKaXkR6ebEPYCHofImX0jYltF51uWW__7Pmb6PmZnut28cSNl4t-5tY6bKtZW2xhSZMvfh3XgC-C9SkMZ6fKyWXKsUcntde4fiihgayFV6LyC3eCaVSuIf/s320/20241202_165012.jpg" width="180" /></a></div><br /><div style="text-align: left;">(This is from project 62 and it's my most perfect panel to date. No crease in sight.)</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Step five: The final touches.</span></b></div><div style="text-align: left;">When the panel is dry, cut out the parts that are covering the holes you drilled with a very sharp knife. <span style="color: #fcff01;">Take your time with this, don't rush it.</span> You can ruin it otherwise. Use a very sharp knife to clear the holes and make a scissor action (cut) against the metal of the panel holes, so you don't pull on the image layer. Pull out the bits you cut out, from the underside of the panel with tweasers so you can't rip off the decals by accident. When that's done I always take a cigarette lighter and move the flame quickly under the holes, from the underside, to burn off any small bits that didn't come off. Don't overdo it though. Be careful.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirNvlxRnkLjIubyvQyfOcTxn9_qwxVFU3kMslRmQtBMdxSRh05ky7nYwFytJ_82dmKL-skcbWKcGCkMp0LoITHoO8CRCHOoKJTz7v3F1ajp1t8pbyeh5Nzzd0M79iHgw9sK9qXFPliKXiGwRjU_uhYy1Yq606gWUpTZvrTuUdEx9g1mwkE-FZ0YslXFSrP/s4000/20241202_170710.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirNvlxRnkLjIubyvQyfOcTxn9_qwxVFU3kMslRmQtBMdxSRh05ky7nYwFytJ_82dmKL-skcbWKcGCkMp0LoITHoO8CRCHOoKJTz7v3F1ajp1t8pbyeh5Nzzd0M79iHgw9sK9qXFPliKXiGwRjU_uhYy1Yq606gWUpTZvrTuUdEx9g1mwkE-FZ0YslXFSrP/s320/20241202_170710.jpg" width="180" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">After that you must coat it again with a few thick layers of clear lacquer and leave it to dry for a day. When that is dry you can put in all the knobs, switches and sockets. Be liberal with the application of clear lacquer. For my last two panels I put on one really thick layer. Because it stays flat all the time you don't have to worry about the lacquer running. The thicker the layer the better when putting in the components because it will prevent the waterslide decals from tearing when you screw things down.</div><div style="text-align: left;">When you're using matte lacquer instead of glossy then do NOT apply thick layers. Matte lacquer has a tendency to bubble and make a rough surface when you apply it too thickly.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">When you put in anything that needs screwing down, and that's everything, make sure there are rings underneath so the screwing action doesn't cut into the waterslide material. This is a bit problematic with sockets because they don't come with rings, so be careful when you tighten them. (The thick layers of lacquer really helps prevent this) You can hold the screw and turn the socket or potmeter from behind the panel, do what you think works the best for you. Most of the time you will damage the layer slightly by putting in the potmeters, that can't always be helped but if you put enough lacquer over it, the damage will be minimal and covered by the knobs you put on the potmeters.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">And that's all there is to it. Anyone with a computer and a printer can do this. I do advise to make a practise piece first and use it to hone in your skills. Here's a look at the Thomas Henry 2164 VCF/VCA in use in my Nifty Case. It sounds amazing and looks amazing too.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjj_3gVJXjJ-yKcMOCdLFF1szZ0xvc7zKYm_iApRYQupmMMdAjf-s-FltBFYOxTFE0udKoatSB4bExWvTsXWdTKdE3L9fcMlnmlFsDXpKoJBeaaVK6hVlwEv7rtIaTDfxRCmfaYvoaqu8UozgQVrOL1pJvrshgEV31aSmaIZIomH1BBlYQyaIpLB289ss4g/s4000/TH%202164%20VCF%20VCA%20in%20Nifty%20Case.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2700" data-original-width="4000" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjj_3gVJXjJ-yKcMOCdLFF1szZ0xvc7zKYm_iApRYQupmMMdAjf-s-FltBFYOxTFE0udKoatSB4bExWvTsXWdTKdE3L9fcMlnmlFsDXpKoJBeaaVK6hVlwEv7rtIaTDfxRCmfaYvoaqu8UozgQVrOL1pJvrshgEV31aSmaIZIomH1BBlYQyaIpLB289ss4g/s320/TH%202164%20VCF%20VCA%20in%20Nifty%20Case.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCjMLtxC9IWRpGzOyhyphenhyphensLlkvuTuFu56l8tccBP-2951ChBNsDGY61lMcOwhXlLV8ADVR0G-AAGVIfKZSTIUVL3NILoi-f_wjxuUcKM9k1_9Qfja29NmklBJb3evkt8G4br-FTwkBudpc-2S-BZRdNKJMnIGGj4Z-cmIq2GxC7ZHjMKlJ0do9qdm50UwgtN/s4000/Ready%20VCF-VCA.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCjMLtxC9IWRpGzOyhyphenhyphensLlkvuTuFu56l8tccBP-2951ChBNsDGY61lMcOwhXlLV8ADVR0G-AAGVIfKZSTIUVL3NILoi-f_wjxuUcKM9k1_9Qfja29NmklBJb3evkt8G4br-FTwkBudpc-2S-BZRdNKJMnIGGj4Z-cmIq2GxC7ZHjMKlJ0do9qdm50UwgtN/s320/Ready%20VCF-VCA.jpg" width="240" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">VIDEO TUTORIALS:</span></b></div><div style="text-align: left;">I found a few video tutorials on YouTube that show the proces from beginning to end. These are all about guitar pedals but it works the same as with synthesizer panels.&nbsp;</div><div style="text-align: left;">I urge you to watch these before you start, so you have a good idea of what's involved.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><a href="https://www.youtube.com/watch?v=XldVuRI41EY" target="_blank">--- CLICK HERE FOR TUTORIAL ---</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><a href="https://www.youtube.com/watch?v=d2LF5hIHj2I" target="_blank">--- CLICK HERE FOR ANOTHER TUTORIAL ---</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Okay that's it for this one. I hope this is of use to you. If you have any questions or remarks please put them in the comments below. They won't appear directly, comments are moderated, but everyone of them is answered by me. You can also post your questions in the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook Group for this website</a>.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-7637683171739104742
title: Synthesizer Build part-60: 4046 WAVESHAPER by Barton Musical Circuits.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/10/4046waveshaper.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">This is the Barton Musical Circuits BMC33, 4046 Waveshaper from 2015. <span style="color: #fcff01;">Not to be mistaken for a wavefolder.</span> This module divides and multiplies an incoming signal by x8, x4, x2, x1, /2, /4, /8 and then you can mix these signals back together to create really awesome timbres. It's a Eurorack friendly design.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDd8eWCZqlEF_dXqvZJrK2UJmnlouwgJiKyaO4Jv2Qfey2Su9L1Vc1l4DFCjzXVa-ss5TRXImT3vdPwEBJzcTjsCfW7oJQh568CJmabd6u5W2Rx0O_5aQsL93rJVPFFTrEBvPqEBK3SCG0oVnUDJ1FkhzyBInh2RXkq0HIcJe8xDbRyLrPoeKytvp7_h9/s4000/Waveshaper%20w%20knobs.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDd8eWCZqlEF_dXqvZJrK2UJmnlouwgJiKyaO4Jv2Qfey2Su9L1Vc1l4DFCjzXVa-ss5TRXImT3vdPwEBJzcTjsCfW7oJQh568CJmabd6u5W2Rx0O_5aQsL93rJVPFFTrEBvPqEBK3SCG0oVnUDJ1FkhzyBInh2RXkq0HIcJe8xDbRyLrPoeKytvp7_h9/s320/Waveshaper%20w%20knobs.jpg" width="180" /></a></div><br /><div style="text-align: center;"><span style="font-size: x-small;">The finished module</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;">This analog circuit uses a CD4046 PLL (Phase Locked Loop) chip in combination with a CD4040 binary counter to create new timbres and waveshapes. It outputs only squarewaves. It's a really simple concept. You take a VCO signal, turn it into a squarewave by means of an opamp comparator and then multiply the signal x8, x4, x2 and x1 while also dividing it by /2, /4 and /8. Now you have 7 signals each an octave apart and each have a potmeter to set their respective levels which go into a little mixer and are output as one new signal.</div><div style="text-align: left;">It has a Slew switch which changes the capacitor of the filter inside the PLL chip, the CD4046. With higher capacitance the tuning will be more stable (especially at lower frequencies), but the tracking of the notes is slower which you can hear as a sort of glide or portamento effect between the notes. It makes a real difference. Makes it sound more SH101 or Acid like if you rapidly change notes. Some of the sounds it can produce can sound like what you get from a wavefolder although that's a completely different concept. The waveSHAPER can produce a lot of other sounds too.</div><div style="text-align: left;">You can alter this circuit and add CV inputs for each of the controls but I didn't do that. I saw a video by Analog Output who did this and he used little VCA's made with logic chips but that will only switch each channel on or off as far as I understood. Anyway, I'll leave the alterations up to you the builder of the project.</div><div style="text-align: left;">Btw, the output volume or amplitude of the output signal can be quite a bit higher than the input signal but it won't damage anything. You could add a overall level control on the output but that would make the faceplate design too big for my taste.</div><div style="text-align: left;">This project will work on both dual 12V and dual 15V.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here is the schematic I used for my layout design:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYEu3jtZWfHPEcH4yHiXSOz-jMOh5VKLUTMHwPo4Z7LmSgm-H4ApMxzE4Pz8lDAPafiqdS2G0ZVFyV39Ce8tTVG9gwX04ZWTpjH2WfRWkG912yj0bpdxiN30-bXQy0PcFShKV7Z_tPFO-0gnBkIr5fmCktFRGE0f9DQk0hWDLuHgn0QE-rSOBdaPBuS2Qw/s1118/Waveshaper%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="762" data-original-width="1118" height="218" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYEu3jtZWfHPEcH4yHiXSOz-jMOh5VKLUTMHwPo4Z7LmSgm-H4ApMxzE4Pz8lDAPafiqdS2G0ZVFyV39Ce8tTVG9gwX04ZWTpjH2WfRWkG912yj0bpdxiN30-bXQy0PcFShKV7Z_tPFO-0gnBkIr5fmCktFRGE0f9DQk0hWDLuHgn0QE-rSOBdaPBuS2Qw/s320/Waveshaper%20schematic.JPG" width="320" /></a></div><div><br /></div><div>There is a PDF file available on the Barton Musical Circuits website which contains this schematic plus a lot of extra info. You can download it by <a href="https://www.bartonmusicalcircuits.com/4046/documentation.pdf" target="_blank">--- clicking here ---</a></div><div>If you want to hear what the module sounds like, there are two demo videos further down the article.</div><div><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Here are the layouts for this circuit. They are verified as always. I used a piece of stripboard that is 24 strips by 30 holes wide which makes it small enough for Eurorack but it will be 6 centimeters deep if you fit it vertically behind the faceplate, so it won't fit a Nifty Case for instance. If you use a 14hp (7CM) wide faceplate you can mount it flat and then it'll be just under 4CM deep.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Wiring diagram:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG-lkYebuKWqY5ydmc_7DYGWzYBzYTCRjxajZTQ0iZsmvPKPUBgd5oRb0KVS3qC3Mz4OaEQ4LAV1vJZHzguPGKHjSud3QoB9iwiTzHTILaNlwX6ZEYemKOZMJsjjfRZjnhb_2WfTdwRwePucq1gEgHiItr9KYaAFEq6W8seC0is_jdGHfeyBXwKI3ap58G/s7813/01%20Waveshaper%20v2%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4858" data-original-width="7813" height="199" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG-lkYebuKWqY5ydmc_7DYGWzYBzYTCRjxajZTQ0iZsmvPKPUBgd5oRb0KVS3qC3Mz4OaEQ4LAV1vJZHzguPGKHjSud3QoB9iwiTzHTILaNlwX6ZEYemKOZMJsjjfRZjnhb_2WfTdwRwePucq1gEgHiItr9KYaAFEq6W8seC0is_jdGHfeyBXwKI3ap58G/s320/01%20Waveshaper%20v2%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Stripboard only:<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBT_bJu2UqH9oxoKO_o0VE9JqCVJbYBKOG2eQtMK7hVAa1WvrdLTIOfmZnK91jCVijwUcUMKm_IG5fv5_SJQcX5LoQd1AEzrNLlUQi4e5ARLKQSIP9N-6qULzH7oxPG_8Uc8ljmxehH2Br9_zUdRxaPyoALNugoQWwS_68uFHyPGH8lGBnh0PxAq1jAPDh/s5000/02%20Waveshaper%20v2%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2778" data-original-width="5000" height="178" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBT_bJu2UqH9oxoKO_o0VE9JqCVJbYBKOG2eQtMK7hVAa1WvrdLTIOfmZnK91jCVijwUcUMKm_IG5fv5_SJQcX5LoQd1AEzrNLlUQi4e5ARLKQSIP9N-6qULzH7oxPG_8Uc8ljmxehH2Br9_zUdRxaPyoALNugoQWwS_68uFHyPGH8lGBnh0PxAq1jAPDh/s320/02%20Waveshaper%20v2%20-%20Stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here are the cuts that need to be made and wirebridges to be soldered in first:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjE5P7ZOg2bnEB5HK7K7J2pDJDMPFd69P9OCZ7yLidFedKqKKiJkjLDvAFMuaF7dJH7d140ntIKACnYDtOSOFeh1MXXQW21U4L-hIkmaSByJpDYfPQtUxhktzLYNFYP-DEkHWfnXu8W3HTH7c9l_orZqLZPvCtJE060bsA1fSWGGgzqIxjgHhd2rxZklX8/s3453/Waveshaper%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2486" data-original-width="3453" height="230" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjE5P7ZOg2bnEB5HK7K7J2pDJDMPFd69P9OCZ7yLidFedKqKKiJkjLDvAFMuaF7dJH7d140ntIKACnYDtOSOFeh1MXXQW21U4L-hIkmaSByJpDYfPQtUxhktzLYNFYP-DEkHWfnXu8W3HTH7c9l_orZqLZPvCtJE060bsA1fSWGGgzqIxjgHhd2rxZklX8/s320/Waveshaper%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><br /><div>And finally the cuts as seen from the component side. You know the routine but I'll repeat it anyway; mark the cuts with a black Sharpie or Edding felt pen and then stick a pin through the marked holes and mark them again on the copper side. Then you can cut the strips at the marked locations using a sharp hand held 6- or 7mm drill, or whichever method you prefer.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJcLHRrtLNYwZdvjzf7spdcZT-zVhZdyMs1_a7x3apK-t4dOSgGcSeS5s47lGeGX8A3PhaCxCkh1n2KvLZlmCfgbLZkkxU6iwpUaBFR80Vs73lbQQLSM2fByzU0W-vOasGJfxSNF0okkpuB3UXizbfVM1dDOa_DpOfdH0Rcvcue6ezqHtIcjJ8BOR4nPcK/s3586/Waveshaper%20cuts.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2597" data-original-width="3586" height="232" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJcLHRrtLNYwZdvjzf7spdcZT-zVhZdyMs1_a7x3apK-t4dOSgGcSeS5s47lGeGX8A3PhaCxCkh1n2KvLZlmCfgbLZkkxU6iwpUaBFR80Vs73lbQQLSM2fByzU0W-vOasGJfxSNF0okkpuB3UXizbfVM1dDOa_DpOfdH0Rcvcue6ezqHtIcjJ8BOR4nPcK/s320/Waveshaper%20cuts.jpg" width="320" /></a></div><br /><div>Here is the bill of materials:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwoHWvQFExKMWlBr9D7XxdMNisWF2kV6i11hZcK2L2dLt6QB-cM8oZy2EuTKrkXkEZZfLBUFOnbJGeiXV0_UHfy9kjCbirlA_KVqUqSWVuONOconpy3whfFZA9nroGsLXPYEeHxnaSuJx7eQD_pCnh1_5PA1Si5p2TmsKtyDJOlNfOSv8T3jPcgy66855i/s836/Waveshaper%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="311" data-original-width="836" height="119" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwoHWvQFExKMWlBr9D7XxdMNisWF2kV6i11hZcK2L2dLt6QB-cM8oZy2EuTKrkXkEZZfLBUFOnbJGeiXV0_UHfy9kjCbirlA_KVqUqSWVuONOconpy3whfFZA9nroGsLXPYEeHxnaSuJx7eQD_pCnh1_5PA1Si5p2TmsKtyDJOlNfOSv8T3jPcgy66855i/s320/Waveshaper%20BOM.JPG" width="320" /></a></div><br /><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures from the build proces. It was pretty straight forward and the layout turned out to be faultless but I made some silly mistakes when wiring it all up. I had the wire that grounds all the potmeters and sockets soldered to the -12V connection instead of the ground and I had the input and output reversed. Can you believe it? After 60 projects I still make these mistakes. It goes to show never to let your guard down and keep working precise and don't rush it, which was my problem.</div><div>Wirebridges put in and cuts made.</div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDGnSE7Wyxbcu8FV0YN_0npNHnJ0avGo5BIoU7tBlAUKwQLMUwvQwS6HLl5M6Sz7yqMo_lmS7SFabdqZJK51wCfKkANH85yGHxUakgwMTgmFC31eeCHmRne4D92rTcCxGBoSFIhRGvWEFzzeH-gvRUy2UQasYaPkk4ZoUEeHxf4OL1_x7qYgvoZUnzAHfm/s2585/Waveshaper-wirebridges%20put%20in%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1904" data-original-width="2585" height="236" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDGnSE7Wyxbcu8FV0YN_0npNHnJ0avGo5BIoU7tBlAUKwQLMUwvQwS6HLl5M6Sz7yqMo_lmS7SFabdqZJK51wCfKkANH85yGHxUakgwMTgmFC31eeCHmRne4D92rTcCxGBoSFIhRGvWEFzzeH-gvRUy2UQasYaPkk4ZoUEeHxf4OL1_x7qYgvoZUnzAHfm/s320/Waveshaper-wirebridges%20put%20in%20Ps.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: left;">Stripboard built up. As you can see I did not include the 10µF capacitors over the power rails. They are in the layout but I usually only include features like that when I have problems with hum or ripple on the voltage lines. With this design you can leave them out. I put in 1µF caps over the outputs because I misread the schematic at first. The dot before the 1µF on the schematic is very difficult to see but it makes no difference for the working of the module; they're just DC blockers here.</div><div class="separator" style="clear: both; text-align: left;">As usual I didn't include 100nF bypass caps over the chips, although you can include them if you want. They're not in the bill of materials.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkqWWqUkytqHYZj61uOm0ng3AhRS_4BTC6EPoaQCFYOzcLkrWlfD6fDurl4cLonHo6X79KNlnlp1qH9hkMTsrWQl9d58QvC3p4s2d-a1OWIb-0I7PG3_3UpJ4DHj8NzizOFchGYq0FtzfOIHUNrYj0950EHNjKI0Jja_JwDCkOk-0tXv1Omj5PhiBMBmD8/s2513/Waveshaper-stripboard%20built%20up%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1606" data-original-width="2513" height="205" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkqWWqUkytqHYZj61uOm0ng3AhRS_4BTC6EPoaQCFYOzcLkrWlfD6fDurl4cLonHo6X79KNlnlp1qH9hkMTsrWQl9d58QvC3p4s2d-a1OWIb-0I7PG3_3UpJ4DHj8NzizOFchGYq0FtzfOIHUNrYj0950EHNjKI0Jja_JwDCkOk-0tXv1Omj5PhiBMBmD8/s320/Waveshaper-stripboard%20built%20up%20Ps.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: left;">Here's the panel design I made for it. I really got a taste now for using waterslide paper to make these panels. It looks so professional. Only I made a mistake....&nbsp;</div><div class="separator" style="clear: both; text-align: left;">I made a typo. The plus signs should be multiply signs. Aaaargh!!! Oh well, I'm not making a new one. ^___^&nbsp; It came out looking great. The faceplate is 10hp or 5 centimeters wide.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfyL5yH8wK_URSYraTuwBROrCeGWCYD5YP56HX-Q1DyG7XKcYdoh0N-lj-fnh-SPBqfF4xIWjevChJL-jpLtBfSw3IVOf3XTOPd4s1bNh_pTaaAA8Ezw1b0uVuKK5PCmXRjl9VwzSboZwj-mzeA0Wm1oUoo257r8OZ4ltm6QV7A2LiUBaVZyErOGczIizI/s3448/Waveshaper-Panel%20dried%20Ps.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3448" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfyL5yH8wK_URSYraTuwBROrCeGWCYD5YP56HX-Q1DyG7XKcYdoh0N-lj-fnh-SPBqfF4xIWjevChJL-jpLtBfSw3IVOf3XTOPd4s1bNh_pTaaAA8Ezw1b0uVuKK5PCmXRjl9VwzSboZwj-mzeA0Wm1oUoo257r8OZ4ltm6QV7A2LiUBaVZyErOGczIizI/s320/Waveshaper-Panel%20dried%20Ps.jpg" width="209" /></a></div><div><br /></div><div>Front and backside view:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIu-C_uRvbzsuL_alth83lsYlaoTlMXBYiPRFXD7pjn7ZBH1pxd1iW52YOsT6YUm-f_4K4rGvmSzHCwmiZZP7xtTFJ1pu8wWMMn4GgGEETBFt10z_6zeBf7iE8wQpARDdzJVSArTPYqQcA66MvLLexbYqJKU3ZAXZQ0naWZxMHtHWWFnjWEW5twbdhN4qJ/s4295/Waveshaper%20front%20and%20backside%20view.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="4295" height="298" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIu-C_uRvbzsuL_alth83lsYlaoTlMXBYiPRFXD7pjn7ZBH1pxd1iW52YOsT6YUm-f_4K4rGvmSzHCwmiZZP7xtTFJ1pu8wWMMn4GgGEETBFt10z_6zeBf7iE8wQpARDdzJVSArTPYqQcA66MvLLexbYqJKU3ZAXZQ0naWZxMHtHWWFnjWEW5twbdhN4qJ/s320/Waveshaper%20front%20and%20backside%20view.jpg" width="320" /></a></div><div><br /></div>The module on the test bench. In the image at the top of this article you can see the finished product with knobs on the potmeters. I found these beautiful small aluminium alloy knobs on ebay. Here's a link to that item:<div><br /></div><div><a href="https://www.ebay.com/itm/333393712610" target="_blank">--- CLICK HERE ---</a><br /><div><br /></div><div class="separator" style="clear: both; text-align: left;"><b><span style="color: red;">OSCILLOSCOPE SCREENSHOTS:</span></b></div>Here you can see how all these squarewaves of different frequencies are summed together and output through the mixer stage. Note how much higher in voltage the output signal is (in yellow) to the original signal (in blue). Both channels are set to 5V per division.<br /><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpeHrLnugBJ_OkcLz1uyPom71gUr0D7C_deefzJ2uIOGYO15mPXS_F2KwuM9LqXCroZLRRc6TrWg1irQxLKVBeQk34hqURazzFGftHRQZw4cK-LCDOyubbCE8cBGgi8C_rP4qN6-cdsvkdn64Dy5iWh6p5ozaYog2RXD_I9OtxSET8gBhPZXOe-6UnKWht/s800/Waveshaper%20output-1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpeHrLnugBJ_OkcLz1uyPom71gUr0D7C_deefzJ2uIOGYO15mPXS_F2KwuM9LqXCroZLRRc6TrWg1irQxLKVBeQk34hqURazzFGftHRQZw4cK-LCDOyubbCE8cBGgi8C_rP4qN6-cdsvkdn64Dy5iWh6p5ozaYog2RXD_I9OtxSET8gBhPZXOe-6UnKWht/s320/Waveshaper%20output-1.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-IK1bN9m9dPxAZzaYdC7qOP0PWafZfp7xBjiJfsH-NGjK-3UEIi-v3CUzwaTo8EhyPFTQs61R4XVdb0AqRG_NNCO8B-Lp4ofbZ_fqxkHJ08JmJgKcvfXU6o3ci5SnHWrN_2BgR-8ACX9hCfuhMh_Cjj-YSoFGCyikuRICwlCYjkmDkGFx8fpy7MkWtAyp/s800/Waveshaper%20output-2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-IK1bN9m9dPxAZzaYdC7qOP0PWafZfp7xBjiJfsH-NGjK-3UEIi-v3CUzwaTo8EhyPFTQs61R4XVdb0AqRG_NNCO8B-Lp4ofbZ_fqxkHJ08JmJgKcvfXU6o3ci5SnHWrN_2BgR-8ACX9hCfuhMh_Cjj-YSoFGCyikuRICwlCYjkmDkGFx8fpy7MkWtAyp/s320/Waveshaper%20output-2.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_v5DGldVdoYRs-61b0xqWqMhTiD9A_WAnqWrdt5Xni-Zgh5lY_X12-lWFoxdD5JC4n-69hfF_D3C3BuAheH_y0ID2U6K2knvh1io0D3VlhpJh8YiTOa1eSfTgZ3-WaPfenfOCJCODw2Y0uBsBv_UC8jW19DEZYkbvIhh8ITf6RUoZsJq1HsTTYj77iLrp/s800/Waveshaper%20output-3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_v5DGldVdoYRs-61b0xqWqMhTiD9A_WAnqWrdt5Xni-Zgh5lY_X12-lWFoxdD5JC4n-69hfF_D3C3BuAheH_y0ID2U6K2knvh1io0D3VlhpJh8YiTOa1eSfTgZ3-WaPfenfOCJCODw2Y0uBsBv_UC8jW19DEZYkbvIhh8ITf6RUoZsJq1HsTTYj77iLrp/s320/Waveshaper%20output-3.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><div><b><span style="color: red;">VIDEO DEMOs:</span></b></div><div>Here's a good demo video I found on YouTube by username Midiverse - TV. Although playing music inbetween the demo bits is not a good idea in my opinion:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/WcAFAW3IVic" width="320" youtube-src-id="WcAFAW3IVic"></iframe></div><br /><div>And here's an other one by youtuber: Boogdish:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/Ohz9AcCIUCY" width="320" youtube-src-id="Ohz9AcCIUCY"></iframe></div><br /><div>Okay that's it for article number 60. SIXTY!! I can hardly believe it. This site has become quite an archive for synthesizer projects and a lot of people seem to really enjoy it. Last month we passed the one million all time views!!</div><div><br /></div><div>If you have any questions or remarks about this project then please put it in the comments below or post in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook group for this website</a>.<br /><div style="text-align: left;"><br /></div></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-3162660703543602051
title: Synthesizer Build part-61: TRIPLE SLOTHS chaotic voltage sources.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/10/TrippleSlothDIY.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">The triple sloths by Nonlinearcircuits is a chaotic modulation source. It has 11 outputs that produce slowly changing voltages that follow a chaotic path. Great for generative patches and ambient music.</div><div style="text-align: left;">The module will fit in a Eurorack Nifty Case. I also made a layout for Kosmo sized modules.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">This is a module I wanted to build for a long time and I finally got 'round to building it. This module produces random control voltages. We have 3 boards, Torpor, Apathy and Inertia. Torpor has the fastest changing voltages. It takes about 15 to 30 seconds to travel around 2 strange attractors, if you watch the plot on an oscilloscope set to X-Y display. Apathy takes about 60 to 90 seconds and Inertia takes about 30 to 40 minutes. Sloths cycles but it never repeats itself! It evolves.</div><div style="text-align: left;">Torpor and Apathy both have a potmeter. The potmeter doesn't change the frequency as you would expect but it changes the tendency of the waveform to be attracted to one or the other attractor. It nudges the waveform in a different direction you might say, that's why I labelled the potmeters 'Nudge'.</div><div style="text-align: left;">Inertia doesn't have a potmeter or a CV input. It just does it's own thing.</div><div style="text-align: left;">Torpor and Apathy have CV inputs, Most of the time a CV input signal will be added on top of the output signals of the module but it can also have the effect of changing the path of the voltages.</div><div style="text-align: left;">You can use an output from one stage to input into an other stage to get even weirder voltage paths.</div><div style="text-align: left;">We have an X, Y and Z output for each stage. Each of these outputs are taken from a different part of the circuit and the Z output is simply the inverted version of the Y output. The two extra Z outputs at the bottom are made up like this: V (Z3+) = Vz Apathy + Vz Inertia - Vz Torpor if greater than 0 otherwise it's 0V.</div><div style="text-align: left;">V (Z3-) = Vz Apathy + Vz Inertia - Vz Torpor if smaller than 0 otherwise it's 0V.</div><div style="text-align: left;">Beware that the voltages summed together can add up to + or -10V so attenuation on those signals would be a good idea.</div><div style="text-align: left;">The X outputs are the lowest in voltage. They stay between +/- 2.5Volt. It will cycle around the 0V line.</div><div style="text-align: left;">The Y outputs vary around +/- 5Volt. They will stay positive for a while and then go negative for a while.</div><div style="text-align: left;">The Z outputs are the same as the Y outputs only inverted.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: #fcff01;">With testing the Sloths on one board, I found the X output voltages of the Apathy and Inertia circuit much higher than +/- 2V. So I tried putting in voltage dividers but when I then mounted the board behind a panel the X voltages were suddenly too low. Really puzzling.&nbsp;</span></div><div style="text-align: left;"><span style="color: #fcff01;"><span>I ended up taking out the 1K resistors to the X outputs of the two problematic circuits and putting in 10K trimmers on the copper side. That solved the problem because I can now dial in the voltages from the X outputs. I connected pin 1 of the trimmer to pin 1 of the TL074 (the signal source). The wiper of the trimpot went to the X output strip and pin 3 of the trimmer went to ground which is the strip below the output.</span>&nbsp;See picture below.:</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgNc6GFoOLN29jvkj_TnQfcFNFm84ywvkZWpiFuiHS9vPoNRE1aVyc6A_37nZv-vS8kb08RUgptFHQ_OY9TTZAc3WdY2MfUYz-k_DPj3D349fK4ELxXxnVdtbth3qQcraWoMvfNbAjIs5TxuYnvJChOJd3sl2y9PpdeulAQnBI2jfDO33p-Fix0RqpgFLB/s4000/Trimmers%20X%20outputs.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgNc6GFoOLN29jvkj_TnQfcFNFm84ywvkZWpiFuiHS9vPoNRE1aVyc6A_37nZv-vS8kb08RUgptFHQ_OY9TTZAc3WdY2MfUYz-k_DPj3D349fK4ELxXxnVdtbth3qQcraWoMvfNbAjIs5TxuYnvJChOJd3sl2y9PpdeulAQnBI2jfDO33p-Fix0RqpgFLB/s320/Trimmers%20X%20outputs.jpg" width="320" /></a></div><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Below are the layouts I made for this module. As always they are verified. I used them to build my module. We have a stripboard for each of the three stages and one for the extra two Z-3 outputs that mix the Z outputs from all 3 modules together.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here is the overall layout showing all boards (Kosmo size layout further down).&nbsp;</div><div style="text-align: left;">[EDIT] on Nov. 6th 2024 I made a slight alteration to the layouts. I routed the LED output through the left over opamp so that is doesn't pull down the voltage of the Z output.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsT-0zEDmeSACJyvKFfpYB_qKO571a0ujgn6p8dw7SzeJA-ax_MpgXtzact2C7-nflDCE6KBCi53mPiHniu3JtaJojk06h254JJJbIcBv9CiHecvuu4JF2xZZnmgDe6hyphenhyphenJ_0vdNwhoo8rKCh1G1dkmo0RDwC-_hI2_6u7GgwOTMOynQgkhvC6TH5V41bR2/s9892/00a%20TRIPLE%20SLOTHS%20w%20ext%20Z%20outs%20orig%20-%20overview.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5896" data-original-width="9892" height="191" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsT-0zEDmeSACJyvKFfpYB_qKO571a0ujgn6p8dw7SzeJA-ax_MpgXtzact2C7-nflDCE6KBCi53mPiHniu3JtaJojk06h254JJJbIcBv9CiHecvuu4JF2xZZnmgDe6hyphenhyphenJ_0vdNwhoo8rKCh1G1dkmo0RDwC-_hI2_6u7GgwOTMOynQgkhvC6TH5V41bR2/s320/00a%20TRIPLE%20SLOTHS%20w%20ext%20Z%20outs%20orig%20-%20overview.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Here's a close-up of the two boards with alterred X-outputs, with trimmers. There was no room for normal trimmers so I put in multi-turn ones on the layout below. This will allow you to set the X output voltages to your liking.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS8ThXy8Pt0BkFApw69_Ij3V-G2WWzHImJggC3nUzfeUZVfL27bv35icTg2x2UugkqW_c-xjiZI53vE3tE0YI6FeJiXlPshBcWI8G0JPdTXIj7ajxFdnv7TOyjmQtrUjGdSYSejNMARL8Tp3nuRcg71kZ1TAoDG-tl1QkqKZyuixCKh90bhOF1hyphenhyphen2dPq8l/s6479/TRIPPLE%20SLOTH%20w%20ext%20Z%20outs_trim_on_X-out.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4125" data-original-width="6479" height="204" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhS8ThXy8Pt0BkFApw69_Ij3V-G2WWzHImJggC3nUzfeUZVfL27bv35icTg2x2UugkqW_c-xjiZI53vE3tE0YI6FeJiXlPshBcWI8G0JPdTXIj7ajxFdnv7TOyjmQtrUjGdSYSejNMARL8Tp3nuRcg71kZ1TAoDG-tl1QkqKZyuixCKh90bhOF1hyphenhyphen2dPq8l/s320/TRIPPLE%20SLOTH%20w%20ext%20Z%20outs_trim_on_X-out.jpg" width="320" /></a></div><div style="text-align: left;"><br /></div>There's not much room for the 1µF capacitors but it doesn't matter if the underside of the caps stick out above the resistors a bit as long as the leads are not touching other components. I put in higher value resistors as current limiters for the LEDs because the 470Ω ones recommended in the schematic made the LEDs shine awfully bright. I thought 1K8 would be better, and they are. All non inverting inputs (+) of the opamps in the TL074 are grounded so the strips that connect pin 3 to 12 and pin 5 to 10 must not be cut underneath the chip.</div><div style="text-align: left;">Here's the Torpor board:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6ia1C1HV0AhE4cNdpNr72N4dndG0BNAr_fKdLxRsL_UokIxdkz2Um83tUifBhiS5xhnijFmGN3z6tKlpJS-0xVcIXz6mMdYMmbx57IaeNCDASzz4nOOy4iG-LgO_l020r5-c7VjBrbtQJbeYR3NIQ7w1_6HuRQJ_5b6ZoXsRIO2Y1RzadKgPiuI7w3FRm/s3438/01a%20TRPPLE%20SLOTHS%20orig%20-%20Torpor.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3342" data-original-width="3438" height="311" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6ia1C1HV0AhE4cNdpNr72N4dndG0BNAr_fKdLxRsL_UokIxdkz2Um83tUifBhiS5xhnijFmGN3z6tKlpJS-0xVcIXz6mMdYMmbx57IaeNCDASzz4nOOy4iG-LgO_l020r5-c7VjBrbtQJbeYR3NIQ7w1_6HuRQJ_5b6ZoXsRIO2Y1RzadKgPiuI7w3FRm/s320/01a%20TRPPLE%20SLOTHS%20orig%20-%20Torpor.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Here's the Apathy board (version without trimmer on X output):<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtAAn4aChvGfNbJ1UxF_x59Ujrl5ffUexS8nhHmNwOtDQPcC_eY7h36w3vn8NZX1T8PlCK3ABjePzN2QYhQFCIvtkfhj-Haaq_OUBxMcF9qG2KaKXguwK2He_vs6GKHffmwWrsM5rFjEdC582zoGtYp6lc6UW41Aaa4SUalP2MXBq2YGlU7XAMjPlB6fZE/s3342/02a%20TRIPLE%20SLOTHS%20orig%20-%20Apathy.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3342" data-original-width="3107" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtAAn4aChvGfNbJ1UxF_x59Ujrl5ffUexS8nhHmNwOtDQPcC_eY7h36w3vn8NZX1T8PlCK3ABjePzN2QYhQFCIvtkfhj-Haaq_OUBxMcF9qG2KaKXguwK2He_vs6GKHffmwWrsM5rFjEdC582zoGtYp6lc6UW41Aaa4SUalP2MXBq2YGlU7XAMjPlB6fZE/s320/02a%20TRIPLE%20SLOTHS%20orig%20-%20Apathy.jpg" width="297" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here's the Inertia board (version without trimmer on X output):</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwxmtoe5ZzxjRW2KuwNa4d60fdFR2L8Nip47CL_bempOd9orSmufhy9acbRCIZFoqqOb6qVUFCngsLLh1Bop-ZlDokFRumK8SuAfQfAfTDX1yx5z38MLJIAHMWgxRqMNNZXVwiuK5GZ0xxYnKD6-JnEhiHZrnxr072rcOD8ZE7iWHY3GFw4k7roXH1nfJQ/s3342/03a%20TRIPLE%20SLOTHS%20orig%20-%20Inertia.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3342" data-original-width="2849" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwxmtoe5ZzxjRW2KuwNa4d60fdFR2L8Nip47CL_bempOd9orSmufhy9acbRCIZFoqqOb6qVUFCngsLLh1Bop-ZlDokFRumK8SuAfQfAfTDX1yx5z38MLJIAHMWgxRqMNNZXVwiuK5GZ0xxYnKD6-JnEhiHZrnxr072rcOD8ZE7iWHY3GFw4k7roXH1nfJQ/s320/03a%20TRIPLE%20SLOTHS%20orig%20-%20Inertia.jpg" width="273" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>And finally the extra Z outputs board:</div><div>You tap the Z inputs from the Z-outputs of the three boards.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYk6ECpfIO8RypaSN76FYZnad59DldmP80RuikQSXjYRq7sJFSd4l0GPugXbGfKGYQ54uSW6VHoVQyZzr-2GLgrSXsk5J_-nH_Cs_nQPHfbJyewkUQAJUGiO8GY2uQCyzYdy3yTGX3sVtDnSinDRsJ0BbervOnzTGoKV_A6eXBS3oG52bAd1UNlo1tOaFI/s2937/04a%20SLOTHS%20ext%20Z%20outs%20board.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1691" data-original-width="2937" height="184" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYk6ECpfIO8RypaSN76FYZnad59DldmP80RuikQSXjYRq7sJFSd4l0GPugXbGfKGYQ54uSW6VHoVQyZzr-2GLgrSXsk5J_-nH_Cs_nQPHfbJyewkUQAJUGiO8GY2uQCyzYdy3yTGX3sVtDnSinDRsJ0BbervOnzTGoKV_A6eXBS3oG52bAd1UNlo1tOaFI/s320/04a%20SLOTHS%20ext%20Z%20outs%20board.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>I didn't make any layouts with just the cuts and wirebridges because these are such small boards that you can easily see where the cuts need to be made and where to put the wirebridges.</div><div>Do be aware that the Apathy board has an extra cut in it above the TL074 chip. All boards differ from eachother slightly so do pay close attention when working on them.</div><div><br /></div><div>Here is the Bill of Materials. There are some very high value resistors needed for the Inertia board and I used Bi-polar capacitors on all boards so you need to order these new instead of putting them together by putting capacitors in parallel. I did leave room to do that at the top of the stripboards but it's easier to just order Bi-polar caps. I did have to make my own 100M resistor by putting ten 10M resistors in series and I used three 33M resistors in series to make the 68M resistor. My local electronics store didn't have them. I only had the 2 Watt versions of those so they took up a lot of space. I should have just used six 10M resistors in series for that one too. For the 1µF caps I ordered ten 1µF WIMA MKS box capacitors with 5mm distance between the legs. They are not polarized and work very well here although they are a bit bigger than round 1µF bi-polar caps, but it fitted well enough.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3CS3rLlhdC40Nrkl6-viW9itB0sssBZS5Fp8CKzu2sjUBtgDVYH0hIQ6R795OKKW1oszVssymAfGCm0WTNb6qpWBVZ2sHH6OszcMU8O045BF6Lfyt09mfy7MB-d_zlpDqfn3R9lba4-AJWk38AiEOBgTN3hqibywEERqe6eYwTxIms0NZefWckqZ7nrNJ/s866/Triple%20Sloth%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="479" data-original-width="866" height="177" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3CS3rLlhdC40Nrkl6-viW9itB0sssBZS5Fp8CKzu2sjUBtgDVYH0hIQ6R795OKKW1oszVssymAfGCm0WTNb6qpWBVZ2sHH6OszcMU8O045BF6Lfyt09mfy7MB-d_zlpDqfn3R9lba4-AJWk38AiEOBgTN3hqibywEERqe6eYwTxIms0NZefWckqZ7nrNJ/s320/Triple%20Sloth%20BOM.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;"><b><span style="color: red;">KOSMO SIZE LAYOUT:</span></b></div><div class="separator" style="clear: both; text-align: left;">Here's a layout I made later just in case you want to build this for a Kosmo sized setup. In that case you can have all three Sloths on one piece of stripboard and it gives you a little more space to place the capacitors too. Again I made a slight alteration to the previous version in that the LED output is now routed through the left-over opamp so it is buffered and can't pull down the Z output voltage.</div><div class="separator" style="clear: both; text-align: left;">This layout is also verified. I've just finished building this version too.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjisLHYytnuK9q7KUYZ_Zez3TT1MNlGG-GRC3trFt1Pd5fuHyND1Xm8alOHK0_kPHqjJsD-SHSLCeyZJUEz2I-AlooY39OBYSYE_8QfgII5LqEsu1wBGdhIAIxoMOB5smAurdGU7zwKqjZifPJ67EA0A877TrSuks9M_Go18skP7JdNPwDlwUr2keWgqEkE/s7476/00a%20Triple%20Sloths%20one%20board%20orig%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4479" data-original-width="7476" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjisLHYytnuK9q7KUYZ_Zez3TT1MNlGG-GRC3trFt1Pd5fuHyND1Xm8alOHK0_kPHqjJsD-SHSLCeyZJUEz2I-AlooY39OBYSYE_8QfgII5LqEsu1wBGdhIAIxoMOB5smAurdGU7zwKqjZifPJ67EA0A877TrSuks9M_Go18skP7JdNPwDlwUr2keWgqEkE/s320/00a%20Triple%20Sloths%20one%20board%20orig%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">Use the extra Z outputs board posted above to add to this main board.</div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">Sloths one board with extra Z outputs board. Cuts and wirebridges.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmZEnrPiM0Aijzky_Kew_fdwt-pE3wJnr40q-gYOS58BsxkLXWxOV638fU7tU-nJYG8JQiHML7WdV72O7rcVusy6d-PzOnYWloP7Vw3c6R84HFBLqb82DPkCRi6ts2CqlyCxWOQiZD41jbPTEkaFNTqL0IYbGpjUL8q5OA-36agGntnFfGnNR9FaVSNmkH/s6247/Tripple%20Sloths%20one%20board%20-%20cuts%20and%20wirebridges%20v3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4420" data-original-width="6247" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmZEnrPiM0Aijzky_Kew_fdwt-pE3wJnr40q-gYOS58BsxkLXWxOV638fU7tU-nJYG8JQiHML7WdV72O7rcVusy6d-PzOnYWloP7Vw3c6R84HFBLqb82DPkCRi6ts2CqlyCxWOQiZD41jbPTEkaFNTqL0IYbGpjUL8q5OA-36agGntnFfGnNR9FaVSNmkH/s320/Tripple%20Sloths%20one%20board%20-%20cuts%20and%20wirebridges%20v3.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><b><span style="color: red;">SCHEMATIC:</span></b></div><div>Because this is a kit that Nonlinearcircuits is selling to create income, I'm not going to post the schematic here. Instead I'm going to link to it on the Nonlinearcircuits website, because I don't want to negatively impact their revenue.</div><div>The link opens the Triple Sloths page and if you scroll down you'll find a green button marked 'build instructions' and if you click that you can download the PDF which also has the schematic in it.</div><div><br /></div><div><a href="https://www.nonlinearcircuits.com/modules/p/triple-sloth" target="_blank">--- CLICK HERE ---</a><br /><div style="text-align: left;"><br /></div></div><div style="text-align: left;">If you do not want to build it on stripboard you can order the complete kit from nonlinearcircuits instead, with PCB's. That module will be 8hp wide. The one I made is 14hp wide because I needed more space to put three stripboards vertically behind the panel. The kit does require you to solder SMD parts unless you get a singel 4hp Sloth module which is through hole.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">You can have a look at the schematic for the Torpor circuit in this Falstad simulation I made:</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><a href="https://tinyurl.com/2xhlpeal" target="_blank">--- CLICK HERE ---</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">DIY BI-POLAR CAPACITORS.</span></b></div><div style="text-align: left;">If you are having trouble finding bi-polar capacitors, you can make your own. Below here is the schematic for a bi-polar cap made up of polarized capacitors.</div><div style="text-align: left;">The equivalent value of a cap made like this is the same as the value of one of the polarized capacitors, provided you use two caps of the same value. So for instance if C1 is 100µF and C2 is 100µF then the equivalent value of the bi-polar capacitor you created will also be 100µF because each of the two caps is used for one phase of the signal. One for the positive side and one for the negative side.</div><div style="text-align: left;">It might be a good idea to use Schottky diodes for D1 and D2 because of their lower voltage drop and<span style="color: #fff2cc;"> I can not guarantee this method actually works</span>. I just thought I'd mention the option but I haven't tried it myself.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0Y75Y69NpRSZ1RVf9w4-VMo5j6rWtAUqHBBmUyr-R5upK30FYcJ5NPTrzEhpPhOUeBwrn0abgXjNiNRLPS889EX4476BHgZ_xV0HTaDyWdbEBwHydO80Fk62frgMeNTgzjWlXyg1Uf6j2CS__fH6PIkvaWP1bqBAvToLa9QFvoYBhmySzidYNomMzBWEU/s1591/Bipolar%20cap%20circuit.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1123" data-original-width="1591" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0Y75Y69NpRSZ1RVf9w4-VMo5j6rWtAUqHBBmUyr-R5upK30FYcJ5NPTrzEhpPhOUeBwrn0abgXjNiNRLPS889EX4476BHgZ_xV0HTaDyWdbEBwHydO80Fk62frgMeNTgzjWlXyg1Uf6j2CS__fH6PIkvaWP1bqBAvToLa9QFvoYBhmySzidYNomMzBWEU/s320/Bipolar%20cap%20circuit.jpg" width="320" /></a></div>&nbsp;</div><div style="text-align: left;">Bi-polar capacitors are used a lot in audio speaker cross-over filters, so that is one place where you can start looking if you want to buy them new. I tried to Google them and had no problem finding them online. Just use the search terms: bi-polar, bipolair or audio capacitors.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">OSCILLOSCOPE SCREENSHOTS:</span></b></div><div style="text-align: left;">Below are some screenshots I took during testing. You can see the random voltages at work. Yellow is X and blue is Y. You can see that Y has a higher voltage than X. The last one shows what happened when I put a triangle wave on the CV input of the Torpor module. The signal was added on top of the voltage. The first three screenshots below were are from the Eurorack version with the separate boards.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEpMec8ZFmMi2Bu3sWTr7YAFiP8V_AA_zEEAB4oZwBNThQdbVMLKh2audslQKKlMz397mS6TDKbTsqJ6NgoTYsh2PgK_LeM3ioYtRZ855LCcEbMatYpP5WENp2ybfzRCHdXVzW1J515ZIRqAbRjOfBQCipWC5ySTnojl8ZsjxDrZufCWjxUwLDS9JUsfYS/s800/Torpor%20X%20and%20Y%20output.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEpMec8ZFmMi2Bu3sWTr7YAFiP8V_AA_zEEAB4oZwBNThQdbVMLKh2audslQKKlMz397mS6TDKbTsqJ6NgoTYsh2PgK_LeM3ioYtRZ855LCcEbMatYpP5WENp2ybfzRCHdXVzW1J515ZIRqAbRjOfBQCipWC5ySTnojl8ZsjxDrZufCWjxUwLDS9JUsfYS/s320/Torpor%20X%20and%20Y%20output.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTvb27aTpKOzuBGJYxcs1Mm04d9B5AiU5QRmneYwmADgyqlXl7W-KS4pEi4tkd9GiNGaHmqIoHQmdpEwTVaSYYlLGUAhN0ueCmAX-Nt6Wt0-WsigVNu6Cac4zkit6wupcKu_nTXvMcho_cO1H0oQa2ImMoXlxcUh1OJ9jqW0H9HEyq_xn983eZm0PheAu-/s800/Torpor%20X%20Y%20output.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTvb27aTpKOzuBGJYxcs1Mm04d9B5AiU5QRmneYwmADgyqlXl7W-KS4pEi4tkd9GiNGaHmqIoHQmdpEwTVaSYYlLGUAhN0ueCmAX-Nt6Wt0-WsigVNu6Cac4zkit6wupcKu_nTXvMcho_cO1H0oQa2ImMoXlxcUh1OJ9jqW0H9HEyq_xn983eZm0PheAu-/s320/Torpor%20X%20Y%20output.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBMI_up1riNpS26h_wE_3k6mzvhgWFH3KA9EzB5M70l_91vIlcowNXlZTNR-Rb6pvEajdTD9r6qtclaiwmx83CmtEqn4SnpYLzYauaLKIoqW9hyphenhyphenI8qA597amIWsXwihPG0q0AcJtyA7Na_qVubCYv1lGWrH7W1fOxYF7yIA4fbFvg4Xo3OTv4k9fYZ9UBD/s800/Voltage%20with%20CV%20applied%20half%20way%20in.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBMI_up1riNpS26h_wE_3k6mzvhgWFH3KA9EzB5M70l_91vIlcowNXlZTNR-Rb6pvEajdTD9r6qtclaiwmx83CmtEqn4SnpYLzYauaLKIoqW9hyphenhyphenI8qA597amIWsXwihPG0q0AcJtyA7Na_qVubCYv1lGWrH7W1fOxYF7yIA4fbFvg4Xo3OTv4k9fYZ9UBD/s320/Voltage%20with%20CV%20applied%20half%20way%20in.jpg" width="320" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here are some screenshot I took when testing the Kosmo sized stripboard with all three Sloths on one board. These are taken from the X outputs of the three boards.</div><div style="text-align: left;">This is over a timespan of 2 minutes. Yellow is Torpor, blue is Apathy and purple is Inertia. You can see the voltages are not all within +/-2V so I experimented with putting in voltage dividers but that didn't work out well.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXn0gmHWIOHJ_obMjT82oPe5-jDapAKJqV1VWFgQODevLKgAHA8rR61rTHqKQ0xr9yl02rkhLwPDvc9gs_JNokpOe3Wl54IizPmf-aZAXicIHHJB9y4w6g_3TgtxhvPymItYmxDzF7fIvAilyCh99cV5RZF77FVt8QRjSeadg2bqmlilpi2kmYnjmvYC9_/s800/Sloths%20X%20outputs%202%20mins.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXn0gmHWIOHJ_obMjT82oPe5-jDapAKJqV1VWFgQODevLKgAHA8rR61rTHqKQ0xr9yl02rkhLwPDvc9gs_JNokpOe3Wl54IizPmf-aZAXicIHHJB9y4w6g_3TgtxhvPymItYmxDzF7fIvAilyCh99cV5RZF77FVt8QRjSeadg2bqmlilpi2kmYnjmvYC9_/s320/Sloths%20X%20outputs%202%20mins.jpg" width="320" /></a></div><div><br /></div>This one is the same as the one above only with a timespan of 4 minutes.<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQX8KyGROp2qqH5tMFviI1iM3Ku5Ivq3r-lMHO8B-Ywvdfmb2JrzO3hC59zYc4kGlzWGuSlUnE6YiyR-bzkY6sSaABESaeKztnXYMi4-lpB3XOgVyGcnVt40Z0XX-h4JAjtYXDfq4c7mCIctgHEEbt7z5DaILaU9KKpW30zqqxvaRRVFpJzUTKl6h6WBmn/s800/Sloths%20X%20outputs%204%20mins.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQX8KyGROp2qqH5tMFviI1iM3Ku5Ivq3r-lMHO8B-Ywvdfmb2JrzO3hC59zYc4kGlzWGuSlUnE6YiyR-bzkY6sSaABESaeKztnXYMi4-lpB3XOgVyGcnVt40Z0XX-h4JAjtYXDfq4c7mCIctgHEEbt7z5DaILaU9KKpW30zqqxvaRRVFpJzUTKl6h6WBmn/s320/Sloths%20X%20outputs%204%20mins.jpg" width="320" /></a></div><br /><div>Again you can see here that the voltage of the Apathy and Inertia X outputs is much higher than the Torpor X output. I don't know why this is the case because I checked and double checked. I switched IC's etc. but I couldn't find anything wrong.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimFNjJGgIm2vDEa06I1T8I5a7Z5P2CrSuPn2Pb_Uv8l9df7qumVTsTECRLKoNUPefGsEU0mLU4_Vu5rC0GsOqOJ50IEqjN6GTLr3qZ7HP8fvaKBGDHykTdxZX52rmj3QahrGgo8gKqA58bpRx-4RwiJkrXYJuzdZr1-CSDB19iRdXZ6tpZWBROycNwJw44/s800/DS1Z_QuickPrint8.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimFNjJGgIm2vDEa06I1T8I5a7Z5P2CrSuPn2Pb_Uv8l9df7qumVTsTECRLKoNUPefGsEU0mLU4_Vu5rC0GsOqOJ50IEqjN6GTLr3qZ7HP8fvaKBGDHykTdxZX52rmj3QahrGgo8gKqA58bpRx-4RwiJkrXYJuzdZr1-CSDB19iRdXZ6tpZWBROycNwJw44/s320/DS1Z_QuickPrint8.png" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">Here's a series of three screenshots with the X,Y and Z outputs of each circuit after I put in the voltage dividers but before the board was mounted behind a panel. Here's the Torpor:</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnP0hyphenhyphenBL4YquMba2M2qJpvb195jv0P5avgwpfYkEItJFQ2WjVXGTmeXwlDmEp0_vbH_6Ep4k8jfWhAQXwNOxN7RaWXZZe4Xz7u4mYghlMyiMXbCOKKLY56fdUS1b-6LIxsRWTXUndiFoW4JNWQ_DcM9k0jZFXbY6bLkRVX27Jh6SCkWp99oq_XU1JcLIp6/s800/01%20Torpor%20XYZ.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnP0hyphenhyphenBL4YquMba2M2qJpvb195jv0P5avgwpfYkEItJFQ2WjVXGTmeXwlDmEp0_vbH_6Ep4k8jfWhAQXwNOxN7RaWXZZe4Xz7u4mYghlMyiMXbCOKKLY56fdUS1b-6LIxsRWTXUndiFoW4JNWQ_DcM9k0jZFXbY6bLkRVX27Jh6SCkWp99oq_XU1JcLIp6/s320/01%20Torpor%20XYZ.png" width="320" /></a></div>Apathy X,Y &amp; Z:<br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMV6gYEdO1tpPKwqO89XQvHWOEiKuAcx0bAjTlhF7xlRB7PAuVta4LSFRMqBZJJgPx9brPpEJB0PVwtGqqpk69s_ZEKwYlCpUuwcSf6Lz-0TpiviBziLRRZ1NEQaGC0tSmZ6AN2qK0wTZ68Q7Nk_HfBFo7T1Ckk7c2ZCDcOtFIhTOOneMZFIQsVUbEd44b/s800/02%20Apathy%20XYZ.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMV6gYEdO1tpPKwqO89XQvHWOEiKuAcx0bAjTlhF7xlRB7PAuVta4LSFRMqBZJJgPx9brPpEJB0PVwtGqqpk69s_ZEKwYlCpUuwcSf6Lz-0TpiviBziLRRZ1NEQaGC0tSmZ6AN2qK0wTZ68Q7Nk_HfBFo7T1Ckk7c2ZCDcOtFIhTOOneMZFIQsVUbEd44b/s320/02%20Apathy%20XYZ.png" width="320" /></a></div>Inertia X,Y &amp; Z:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqpP0-uEIM7a2Xymcd5rh-0Qs_11dxROg9_tllRGZ6H8jQutENYS_YPVq15NQd1_nL5TfAUWdt3tkF7Rv6jvnD2m_h_-H7GBG3s_zb3WzrARWSluTeUMNIrzERomGoNbDszn7tpcvQ1gCOv_QVP7dXQnt558yfhEe-iIooUXTJhVE6gTj5gevZPYS3QH9O/s800/03%20Inertia%20X-Y-Z.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqpP0-uEIM7a2Xymcd5rh-0Qs_11dxROg9_tllRGZ6H8jQutENYS_YPVq15NQd1_nL5TfAUWdt3tkF7Rv6jvnD2m_h_-H7GBG3s_zb3WzrARWSluTeUMNIrzERomGoNbDszn7tpcvQ1gCOv_QVP7dXQnt558yfhEe-iIooUXTJhVE6gTj5gevZPYS3QH9O/s320/03%20Inertia%20X-Y-Z.png" width="320" /></a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">You may notice that there's not much difference over time in the waveforms, especially the last two but that occurs over time and in very small amounts. Try experimenting with feeding slow LFO signals into the CV inputs of Torpor and Inertia. You can use one output of Sloths to go into the CV input of another Sloths.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Z3 plus output:</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5z3TMtKiskBQmNrtFyZuJG0wvsvht7N3tWaeY8IM33Xymka15Qlm6qswh7YjzTCnf_Jsyna4KfvKJ2K3ngK4bkdPADHuU1YpxqYwbKh05dTD5QY-FxO03-yMLMKXdTrGNLx0DI6Q2S83GKdXuVnMp-1myep7ONhIW0LOIAOQEIOzaFCrjAfKe-HazfhwF/s1297/Z3%20plus%20output%20jpeg.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="777" data-original-width="1297" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5z3TMtKiskBQmNrtFyZuJG0wvsvht7N3tWaeY8IM33Xymka15Qlm6qswh7YjzTCnf_Jsyna4KfvKJ2K3ngK4bkdPADHuU1YpxqYwbKh05dTD5QY-FxO03-yMLMKXdTrGNLx0DI6Q2S83GKdXuVnMp-1myep7ONhIW0LOIAOQEIOzaFCrjAfKe-HazfhwF/s320/Z3%20plus%20output%20jpeg.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Z3 minus output:</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg__e6VFAFHn_f0PUU7O6nvJdyUW0aId1MdisZljTFc01sNg9j9iB-OJ0OMQxOHvjrTy5iDQXLOLKgTYfjcYSZt6SWkRMdsl2tJVpHeyC7vuWuGnUS8gfwCNEiObZNSXXmtYy82cVS0FHpBrkqvlfrrxYXfiXNz5QjwqPrM4D4m6ySiL6vLclKWxpfC6ZXB/s800/Z3%20minus%20output.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg__e6VFAFHn_f0PUU7O6nvJdyUW0aId1MdisZljTFc01sNg9j9iB-OJ0OMQxOHvjrTy5iDQXLOLKgTYfjcYSZt6SWkRMdsl2tJVpHeyC7vuWuGnUS8gfwCNEiObZNSXXmtYy82cVS0FHpBrkqvlfrrxYXfiXNz5QjwqPrM4D4m6ySiL6vLclKWxpfC6ZXB/s320/Z3%20minus%20output.png" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: left;"><br /></div><div><div style="text-align: left;"><div><b><span style="color: red;">PICTURES:</span></b></div></div><div style="text-align: left;">Here are some pictures I took when building the Kosmo version:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpkTdATSddghSSxU773BJyEcoOQbETX9bNGDk3e1ybdaC-Gr53eqjBLooeC6kR8natcBcOBNqNDqNKiYd4qhP92NHhX1KiHrnO73yHx2l2YyUq3OySmTS2S97YtLjqpBw9IRrVytdeogWsP7YUkj8C8heipUJ7aa7fi_fa68NvFtJtRPi8LxKRYVZyUpD6/s3340/One%20board-cuts%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1773" data-original-width="3340" height="170" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpkTdATSddghSSxU773BJyEcoOQbETX9bNGDk3e1ybdaC-Gr53eqjBLooeC6kR8natcBcOBNqNDqNKiYd4qhP92NHhX1KiHrnO73yHx2l2YyUq3OySmTS2S97YtLjqpBw9IRrVytdeogWsP7YUkj8C8heipUJ7aa7fi_fa68NvFtJtRPi8LxKRYVZyUpD6/s320/One%20board-cuts%20wirebridges.jpg" width="320" /></a></div><div><br /></div><div>I made the 100M and 68M from 10M resistors in series. I put small pieces of heatshrink tubing on the soldered ends where the resistors connect to eachother to prevent accidental short circuits. Then I hotglued the resistors in place.&nbsp;</div><div>I didn't have a 39µF bipolar cap so I put in a 22µF (in the Inertia part) and added two polarized 10µF caps with diodes attached like I showed earlier in the article. I'm not sure if it has an influence. The capacity meter doesn't pick up the extra capacity because of the diodes but at least it is working normally.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRh9stY8uZMZm9J1-IFuYdBrNvzmAUep4TPWjIir3-AOzbeTxDRlKkuU3vaiKejobGEO336iA2Tcd3a6XFlG7D_JHnB_Zj0BkfYx9FfPf36JPgUw935tdwY-ZxFh-B3iSRBbwZLVW-pOQ5wsTbTfPqsTYCkO27_WCVCNbYLQ7IxgElCc-zO1SMa51TgCBP/s4000/One%20board-%20testing.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRh9stY8uZMZm9J1-IFuYdBrNvzmAUep4TPWjIir3-AOzbeTxDRlKkuU3vaiKejobGEO336iA2Tcd3a6XFlG7D_JHnB_Zj0BkfYx9FfPf36JPgUw935tdwY-ZxFh-B3iSRBbwZLVW-pOQ5wsTbTfPqsTYCkO27_WCVCNbYLQ7IxgElCc-zO1SMa51TgCBP/s320/One%20board-%20testing.jpg" width="320" /></a></div><div><br /></div><div>With the 100M resistor made up of ten 10M resistors in series I added a center tap point that I connected to a copper strip that was not in use. I wanted to add a switch so I could half the resistance to make the Inertia part of the circuit work a little faster if I wanted to. That didn't work out though. It did go faster after closing the switch but the output voltage also shot up way too high. So do not replicate my experiment.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1M8Jxsd4egRniDVIm61l_PYOy4N6m2R4_YoT8XBD5XRlW22ylWyB-7J55QGHk5TcYqEThPJQ7NqHUvoy5nlDroboVQ1BBS65Dpe-F1pcDOUSDfRrnRuiS5EHRqqSbsjq8jyVb2cmKqsGaKbN7HUabtIbjdWD9IH4oJyurK_WnSEELqJYqiMPSGZS1P5lw/s4000/One%20board-scope%20probes.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1M8Jxsd4egRniDVIm61l_PYOy4N6m2R4_YoT8XBD5XRlW22ylWyB-7J55QGHk5TcYqEThPJQ7NqHUvoy5nlDroboVQ1BBS65Dpe-F1pcDOUSDfRrnRuiS5EHRqqSbsjq8jyVb2cmKqsGaKbN7HUabtIbjdWD9IH4oJyurK_WnSEELqJYqiMPSGZS1P5lw/s320/One%20board-scope%20probes.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Here you can see how I mounted the Z outputs board. It is just floating. The main Sloths board is mounted by putting two sets of copperwire through the ground strip at the top and twisting and soldering them together and then soldering them to the ground connection wire or the sockets. The socket grounds are all connected together with one copper wire going through all the ground lugs of the sockets.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjC5tt3gntq9326lH0BUWu26n32foorT3Av1GtL_XTpT_3I1LOE_FXt6FTPVcpaIqTshadnc_aM2iHlluPsI39ecovlLeLI_zjm3PTBG7xZxJ4e_fNOqdrQ-oZK1bK0UGoQ9lSnJav102hXvac1Uwy-bpWnaHLzwe3vfkku60LH_J-oQKIOaN5a7921EAzx/s4000/Z%20output%20board%20floating.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjC5tt3gntq9326lH0BUWu26n32foorT3Av1GtL_XTpT_3I1LOE_FXt6FTPVcpaIqTshadnc_aM2iHlluPsI39ecovlLeLI_zjm3PTBG7xZxJ4e_fNOqdrQ-oZK1bK0UGoQ9lSnJav102hXvac1Uwy-bpWnaHLzwe3vfkku60LH_J-oQKIOaN5a7921EAzx/s320/Z%20output%20board%20floating.jpg" width="320" /></a></div><br /><div style="text-align: left;">Here's a look at the finished panel mounted in the synth:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghmWA38bXzeSSw7NhhNooIAhWDj6w4WEBUXATisb_qeN4QPimBpkKdINkqxCQKg2g7n4ltJ60ia8-Tx7LBNmvoXs6Qm8Eh9LZ0oZsUEwKqhaAWuHLjlOfed0jgE9mEraFGM-0l-dfA34-wrx1feBm0EFI_Ie6FHyIKefTj4Ti38-FYakztyNPm8-ZvUnoY/s3868/Mounted%20in%20synth.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3868" data-original-width="2060" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghmWA38bXzeSSw7NhhNooIAhWDj6w4WEBUXATisb_qeN4QPimBpkKdINkqxCQKg2g7n4ltJ60ia8-Tx7LBNmvoXs6Qm8Eh9LZ0oZsUEwKqhaAWuHLjlOfed0jgE9mEraFGM-0l-dfA34-wrx1feBm0EFI_Ie6FHyIKefTj4Ti38-FYakztyNPm8-ZvUnoY/s320/Mounted%20in%20synth.jpg" width="170" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Below are some pictures from building the Eurorack version.</div><div style="text-align: left;">Here you can see the 'Inertia' board with the 100M resistor I had to make from ten 10M resistors in series. I made the 68M from three 22M resistors. These were big 2 Watt resistors. In hindsight it would have been better to have used six 10M ¼ Watt resistors in series.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvQapXuKDdXHgMI0IMXXNuvKZZg4xGapeMncu5NMdfoGeXYq7vquaTuOH9Q8XFzjjW4zBzAihrABo1HQqw2yDMa0_ExOKtMKxaZNYoXtwqxD6m2IL6t5gEHAkdq3ZbkBKZJs-ncho4OFeF6QW7VuJqWbhOweSKS6d-VDJhUFcyFz3fdruIbad3AD3atl67/s3280/Big%20resistors.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3280" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvQapXuKDdXHgMI0IMXXNuvKZZg4xGapeMncu5NMdfoGeXYq7vquaTuOH9Q8XFzjjW4zBzAihrABo1HQqw2yDMa0_ExOKtMKxaZNYoXtwqxD6m2IL6t5gEHAkdq3ZbkBKZJs-ncho4OFeF6QW7VuJqWbhOweSKS6d-VDJhUFcyFz3fdruIbad3AD3atl67/s320/Big%20resistors.jpg" width="220" /></a></div><br /><div style="text-align: left;">Here are the three boards together. I soldered powercables to them for testing. When they were mounted behind the panel each board got power from the board beside it with simple daisy chained wire connections. You could use pinheaders but you'll need the extra high version.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">One thing I noticed when testing, which is important to know, is this: I connected the Torpor module to my bench powersupply and it would only produce sinewaves but they weren't random. This turned out to be a fault in my powersupply. When I connected it to my synthesizer powersupply it worked normally.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK70dvlclKsj70bTo4tFq_pdNSx4QV3UUFTGP3rh2TyckNuunwpNBkZ-ymK9KbeixvYz-WuPhB1nxmmDxCSeB-wlFPX-8d_wAwSkpEKg8nc33CB2ULqelpv-i_OHvtudPvHXC7LNnVTdhauBbzi2RadlHvcpAm-y4Q4uoVdm9Tv1EgV9bs76D46fHKerbX/s2872/3%20boards%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2872" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK70dvlclKsj70bTo4tFq_pdNSx4QV3UUFTGP3rh2TyckNuunwpNBkZ-ymK9KbeixvYz-WuPhB1nxmmDxCSeB-wlFPX-8d_wAwSkpEKg8nc33CB2ULqelpv-i_OHvtudPvHXC7LNnVTdhauBbzi2RadlHvcpAm-y4Q4uoVdm9Tv1EgV9bs76D46fHKerbX/s320/3%20boards%20finished.jpg" width="251" /></a></div><div><br /></div><div>Here you can see the backside of the module. Three boards tucked in together with the extra Z outputs underneath. The two outer boards are connected to the faceplate through the potmeter that is soldered straight to the stripboards. The Inertia board has no potmeter and it is mounted inbetween the two others and secured with hot glue.</div><div>Wiring these stripboards up was very time consuming. It took me almost a whole day. Because there is almost no access after the boards are mounted behind the panel, you have to solder the wires to the boards first. Put in all the sockets and ground them all. Then put in the boards and solder the wires to the sockets. To save space I soldered three wires to a Female Eurorack powerconnector and soldered the wires to the Torpor board. The other three boards get their power from the board to the left of it with again three wires. Be careful that non of the components touch the copper strips of the neighbouring boards. I put in gaffa tape and hot glue to protect some areas from short circuits.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfCd8WibgD_esiRKKyOLDx8I6Af8XjPMBcfcakLqsXSu6T7Ua8vxNPmpArWQWB2Vi6jUtR9GHuNNAWoJ65BEA1Lg3NEo6nRZx2YPi7gsYKXqI42zwBlell_kaPQ2LZVfiu_Vi5HxOl-dLzoOe7PjX3mLb39rEXAK0krfJ02CpdEwVxwhEXb5jlsxQwqxJF/s3364/Backside.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3364" data-original-width="1965" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfCd8WibgD_esiRKKyOLDx8I6Af8XjPMBcfcakLqsXSu6T7Ua8vxNPmpArWQWB2Vi6jUtR9GHuNNAWoJ65BEA1Lg3NEo6nRZx2YPi7gsYKXqI42zwBlell_kaPQ2LZVfiu_Vi5HxOl-dLzoOe7PjX3mLb39rEXAK0krfJ02CpdEwVxwhEXb5jlsxQwqxJF/s320/Backside.jpg" width="187" /></a></div><div><br /></div>Here's the finished module with the faceplate made with the waterslide paper method. Again I made a mistake. I forgot the two CV inputs. Well, there was room enough to put them in they are just not labeled. I called my module Sloth, not Sloths for no reason really :-D<br /><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCeSTbk8XNEinNt2jNsqTuVbEeCMtz1k4y8WOGeLgEhRGVldTGHPawUpJs-2hzIQdEYsoRRnNYTAV9xyc52uzEWOYuShue_3lQHXB-nAXFkWRN37Og7NmTc5Dy2jSyy8Oo47mjJx4trxjMEBcQBRJl3Rz1BS4a8QPZm-aiHXBxgfbSjmKSs_mmmdRUTb_G/s3352/Finished%20Module.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3352" data-original-width="2120" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCeSTbk8XNEinNt2jNsqTuVbEeCMtz1k4y8WOGeLgEhRGVldTGHPawUpJs-2hzIQdEYsoRRnNYTAV9xyc52uzEWOYuShue_3lQHXB-nAXFkWRN37Og7NmTc5Dy2jSyy8Oo47mjJx4trxjMEBcQBRJl3Rz1BS4a8QPZm-aiHXBxgfbSjmKSs_mmmdRUTb_G/s320/Finished%20Module.jpg" width="202" /></a></div><br /><div style="text-align: left;">Btw, these knobs are temporary. The ones I'm going to use are slightly larger but they are still in the mail.</div><div style="text-align: left;">When you start designing your panel layout make sure to offset the sockets a little from the potmeter positions. Don't put them straight underneath the potmeters because the stripboards will touch them. Put them slightly to the left. I did make that mistake and I had problems getting the boards to fit.&nbsp;</div><div style="text-align: left;">And like I said before, don't forget to put in the CV inputs. ^_____^</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">DEMO VIDEO:</span></b></div><div style="text-align: left;">First a little demo I filmed myself with the following patch: Sloths Torpor X output goes into the 2hp Tune quantizer which turns the voltage into random notes following a chromatic scale then the 1V/Oct signal from the 2hp goes into the Digisound 80 VCO and from there into a 2164 Lowpass filter which has the cutoff controlled by Sloths Torpor Y output. Although that didn't come out very pronounced.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dyg-9x2r3qRKiC9JD5Tpk2Ow05DpMBEYl0KPrLFsqRzt4ZzUOn7Dh1n1eaKcipXthNGFGyvE9GRkmE0nDhGyg' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><div><br /></div>Here's a little demo of the Kosmo sized Sloths in action with the Torpor and Apathy X outputs controlling the filter cutoff of the TH State Variable Filter and the Lowpass Gate.<br /><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dwlNOs19hthnVXvJUtJ1_nVWTM1Nupd10p5eUyODMRQlB73mKlOD64Z-ABdm_8wpnYS8yE-yeq5r3WE0tarDw' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's a cool video I found on YouTube explaining how this module works:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/y3Sg-Qp5eYU" width="320" youtube-src-id="y3Sg-Qp5eYU"></iframe></div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><span style="color: #fcff01;">TIP: lead the output of one of the sloths (the faster one like Torpor Y output) into the signal in of a Sample and Hold to get random stepped voltages like the Turning Machine produces.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Okay that's another one done.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">If you have any comments or questions about this module then please put them in the comments below or in the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">special Facebook group</a> for this website. Beware that comments are moderated and don't appear until I approved them.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-2633106306898362177
title: Synthesizer Build part-62: 2164 VCF/VCA by Thomas Henry.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/12/2164VCF-VCA.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">This is the Fonitronik Thomas Henry AS2164 state variable filter and VCA in one. THIS FILTER SOUNDS DELICIOUS!!&nbsp; It's a great sounding combination. I used two stripboards that connect together with pinheaders making this a very eurorack friendly design. However this is not a beginner friendly project. You need good soldering skills for this one. Even for me this was not a 'hole in one' like a lot of the previous projects. I made a few mistakes but I found them in the end so all is well. But this project is certainly in my top 5 of best projects on this website.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">This filter uses the AS2164 or V2164 chip which, in its original form, was a chip from SSM (Solid State Music). These chips were used in many late 70's polyphonic analog synthesizers like the Prophet 5 for instance. The V2164 is made by CoolAudio which is a company owned by Behringer which they use to create all the old obsolete chips for Behringer's line of vintage synths that they are reproducing.</div><div style="text-align: left;">The 2164 is not actually a filter chip. It has four independent VCA's on board and in this design two of those are used to make a great sounding 2 pole filter (12dB/Oct.). This filter has that vintage liquidy feel to it when you add a lot of resonance. It sounds amazing.</div><div style="text-align: left;">The left over two VCA blocks in the chip are used to make a single VCA. Of course you don't have to build the VCA if you don't think you need it. You can build just the filter board if you want. However you can not only build the VCA board (using my layouts) for the obvious reason that the 2164 chip is housed on the filter board.</div><div style="text-align: left;">The V2164 chip is very sensitive to missing negative voltage. If negative voltage falls away the chip will be distroyed. There is a diode in the layout that protects the chip however.</div><div style="text-align: left;">If you buy the AS2164 instead of the V2164 then you don't have to worry about this because the AS2164 has internal protection against negative voltage cut out built in. BTW, you can buy the chip(s) from <a href="https://electricdruid.net/product/as2164-quad-vca/" target="_blank">Electric Druid</a>&nbsp;amongst others.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here's the finished module (on the right) fitted into a Nifty Case. Dispite the depth it still easily fits.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgk7Qgamsk8eKGd7r4KE5hWvHW63nkfffOkc5HwAcf_4X1H3slcPZvqXzT7TCD-78JaOSOGfIYreyqCK-jXnhyQCfBy0odSTG1BP5OnXhk6TCty5KDqrZN5d1_t3frhe3JOLvTaGFamfbpUT2r5PZKYUR2ZoVJApJI1GjYhcvcn58coM-ixduwrQ9ND8O1b/s4000/TH%202164%20VCF%20VCA%20in%20Nifty%20Case.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2700" data-original-width="4000" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgk7Qgamsk8eKGd7r4KE5hWvHW63nkfffOkc5HwAcf_4X1H3slcPZvqXzT7TCD-78JaOSOGfIYreyqCK-jXnhyQCfBy0odSTG1BP5OnXhk6TCty5KDqrZN5d1_t3frhe3JOLvTaGFamfbpUT2r5PZKYUR2ZoVJApJI1GjYhcvcn58coM-ixduwrQ9ND8O1b/s320/TH%202164%20VCF%20VCA%20in%20Nifty%20Case.jpg" width="320" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here is the schematic:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCz1n5XjVaHUAmLiJyUw83LMdFN3_k0v5DDoab80BUt6u1gMd0wvXVCmCsqSrRDWTk1qMDNWyf2W2HgjHxneB-lBrQkf_jpuFQEVkZjzT12LDx9IXcdxVd1dme5-aOD2lRwjTVd3Ffqkyvd7kI_zC0hErpziyD1PgxqkVisEt6I_NKQxyYi-X6KVyiS7z4/s3288/TH%202164%20VCF%20VCA%20schematic.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2242" data-original-width="3288" height="218" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCz1n5XjVaHUAmLiJyUw83LMdFN3_k0v5DDoab80BUt6u1gMd0wvXVCmCsqSrRDWTk1qMDNWyf2W2HgjHxneB-lBrQkf_jpuFQEVkZjzT12LDx9IXcdxVd1dme5-aOD2lRwjTVd3Ffqkyvd7kI_zC0hErpziyD1PgxqkVisEt6I_NKQxyYi-X6KVyiS7z4/s320/TH%202164%20VCF%20VCA%20schematic.jpg" width="320" /></a></div><div><br /></div><div><span style="color: #fcff01;">This project will run on both a dual 15V or a dual 12V powersupply.</span> It's designed for 15V as you can see on the schematic but I built it for Eurorack dual 12V and it works fine.</div>As you can see it's quite a simple design and in my experience those produce the best sounds. The top part of the schematic shows the filter and the bottom part the VCA. I decided to make the two parts that make up this module on two separate pieces of stripboard so that I could make them small enough to fit flat behind a 14hp faceplate, with one board on top of the other. They connect together using pinheaders. The VCA board is connected to the 2164 chip via those pinheaders. The depth of the finished module will be around the 4 CM mark.<div><br /></div><div><b><span style="color: red;">LAYOUTS:</span></b></div><div>Below are the layouts I made for this module. As always they are verified, I used them for my build.</div><div><br /></div><div>Here's an overview of both boards. In the layouts you can see a Coarse and Fine control for the filter cut-off. The fine control is there in case you want to use the filter as an oscillator in full resonance, so you can tune it, but I never use a filter like that so in my own project I switched the 3M3 resistor for a 100K one and put in an extra socket so I can use that as an extra CV input with level control, So the potmeter labelled as Coarse is in my case labelled as 'Cutoff' and the 'Fine' control is now my CV2 Level potmeter. I placed it all the way down on the faceplate.&nbsp;</div><div>The PTC is an other component you don't need if you don't want to use this filter as a sinewave oscillator. Just put in a 2K resistor instead. That's what I did too. There's also a 7K5 resistor which I coloured purple, in the layout. Leave that out too. If you include it you change the VCA amplifier type from a class AB to a class A type. Totally unnecessary.</div><div>I used miniature potmeters in this project to save space and I made my own custom potmeter symbols in the layout software, the little green ones.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVBhoDCg5Ubjbi4GxYsjGdBHXJXnHhwR9C2lnvqXsNkAsEIpJhR2eF_6CT2REO3ewZcWrY-ywgDkefJjtj2U2GQ_lfgygP17tbkA32frDp9mnIivqWUc6NdLoNC-BN9gcxeThWYEvGplJhVTCd0uDjsEdeBq0WlGufoH0gcRuDJNigzapiStwSuL11Yk4V/s8976/01%20TH%202164%20VCF-VCA%20overview.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="8392" data-original-width="8976" height="299" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVBhoDCg5Ubjbi4GxYsjGdBHXJXnHhwR9C2lnvqXsNkAsEIpJhR2eF_6CT2REO3ewZcWrY-ywgDkefJjtj2U2GQ_lfgygP17tbkA32frDp9mnIivqWUc6NdLoNC-BN9gcxeThWYEvGplJhVTCd0uDjsEdeBq0WlGufoH0gcRuDJNigzapiStwSuL11Yk4V/s320/01%20TH%202164%20VCF-VCA%20overview.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here's the wiring diagram for the filter part. All potmeters are viewed from the back. It may look to you that the Resonance potmeter is wired the wrong way around with ground at the clockwise position but I found out that this is the right way to do it. Resonance is usually wired the other way around in most filters. This filter, I have to say it again, sounds sooo good. I love 2164 based filters and I think this is now my favourite filter on the website. It has a liquidy watery feel to the resonance which is just amazing. Anyway..... here's the layout for the filter board.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcmQOVmo6iIFmPxBFpA3GjJJ-LIHHOBfO9m-y-V20h8WJ5UiB2KJBq6_NYojUjTVuzvzXza-7iGfRljIzY0F87DIWxN_hXDOGfom65ZP6oO_tDCF7fU9Hkoo-AAZqVtPKHioavzsVag_n1HxyIKsZ_vf7L6MLJTINHWwKW1FCyocvVoIz5jtD6UAx491dr/s8976/02%20TH%202164%20VCF%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4289" data-original-width="8976" height="153" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcmQOVmo6iIFmPxBFpA3GjJJ-LIHHOBfO9m-y-V20h8WJ5UiB2KJBq6_NYojUjTVuzvzXza-7iGfRljIzY0F87DIWxN_hXDOGfom65ZP6oO_tDCF7fU9Hkoo-AAZqVtPKHioavzsVag_n1HxyIKsZ_vf7L6MLJTINHWwKW1FCyocvVoIz5jtD6UAx491dr/s320/02%20TH%202164%20VCF%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>VCF stripboard only view:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGpZScHb62ufKe4SkrCnAQTy6hB3PnrC1j0TZuyvjv4ZsT36iHqoxVAt2-M-s5hq3PbAt_MJfoYLTyYOwndtqmVKtGKfmJjB11nl93EOubxIvPbW9gVDKPPWxMQQgFXOF-8hjBE-lQjA8GEUKCDdU4PECnut3Toca3L6gv6e0PgqV1hB1mN7k_1q1omLaV/s4236/04%20TH%202164%20VCF%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2776" data-original-width="4236" height="210" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGpZScHb62ufKe4SkrCnAQTy6hB3PnrC1j0TZuyvjv4ZsT36iHqoxVAt2-M-s5hq3PbAt_MJfoYLTyYOwndtqmVKtGKfmJjB11nl93EOubxIvPbW9gVDKPPWxMQQgFXOF-8hjBE-lQjA8GEUKCDdU4PECnut3Toca3L6gv6e0PgqV1hB1mN7k_1q1omLaV/s320/04%20TH%202164%20VCF%20stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Below is the wiring diagram for the Linear VCA part. The VCA has two audio inputs. One direct input without level control which is intended more for LFO signals. On the Fonitronik panel it is labelled as DC IN. In my design I did give it a level control but that potmeter is not on the layout. The top audio input has a level control and an AC/DC switch. AC is usually used for audio signals, filtering out any DC components like offset voltages that might be present. DC is used for very low frequency signals like from an LFO or envelope generator; signals that would be distorted if they went through a capacitor first. <span style="color: #fff2cc;">The VCA is very snappy, it can switch on and off very fast so you can use audio rate signals to open and shut the VCA and get a sort of ringmodulator effect.</span></div><div>The 'initial' potmeter regulates the output volume of the VCA by adding an offset voltage to the envelope input. You can use it to open the VCA without pressing any keys so you hear continuous sound. If you close it, the sound will only come through when you press a key and an ADSR signal comes in on the CV input.&nbsp;</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyq893aNRYcaklQGonF12ulfZzyKCKnAV8SzjI8LRRFKbjkxus4MFlXcxAoNtvm3ugDWfNF7adNuxscZMjekq8o6HqyK60886xphSkI3x4gwhjdlpsb48A-0au6kbZMptIDVYRX3_ivBy4Z5kMDJ_s6zTAxBM9WPA0dqBo_nMfyMiq9MUI-1Hs0i_8fwOI/s7631/03%20TH%202164%20VCA%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4138" data-original-width="7631" height="174" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyq893aNRYcaklQGonF12ulfZzyKCKnAV8SzjI8LRRFKbjkxus4MFlXcxAoNtvm3ugDWfNF7adNuxscZMjekq8o6HqyK60886xphSkI3x4gwhjdlpsb48A-0au6kbZMptIDVYRX3_ivBy4Z5kMDJ_s6zTAxBM9WPA0dqBo_nMfyMiq9MUI-1Hs0i_8fwOI/s320/03%20TH%202164%20VCA%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><span style="font-size: x-small;">(Last revised: 16-12-2024: The two potmeters with ground connections were wired the wrong way around. That is now corrected)</span></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>I know that in the schematic the 'Initial' potmeter goes through a 300K resistor and not a 100K like on the layout but I lowered it to 100K because that worked better for me. Should you feel that the Initial potmeter is too overpowering or doesn't work right, then put in a 300K for the bottom 100K resistor.</div><div><br /></div><div>VCA stripboard only view:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_AxBhrA3YqKxcZQ1dsXoAEh7uFcafDFKKQ6A_gTekOS1c3HOHoD9Pb2D0csopbo5AVq09mscSFMaqGxtKNsuQXrIYQlr2-UH4E2GU_yCJ59GjHdOrq9XdsI1hSYTK3oJ168hEA3Q2sCJCdjEoC8S65KyesCaEEqOydezRW8R0WU4RdbIZU3UYPZhk5lOc/s3700/05%20TH%202164%20VCA%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2775" data-original-width="3700" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_AxBhrA3YqKxcZQ1dsXoAEh7uFcafDFKKQ6A_gTekOS1c3HOHoD9Pb2D0csopbo5AVq09mscSFMaqGxtKNsuQXrIYQlr2-UH4E2GU_yCJ59GjHdOrq9XdsI1hSYTK3oJ168hEA3Q2sCJCdjEoC8S65KyesCaEEqOydezRW8R0WU4RdbIZU3UYPZhk5lOc/s320/05%20TH%202164%20VCA%20stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here's an overview of the pinheaders, wirebridges, and cuts to be made for both boards, seen from the component side:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSD464eAGKItk_eI0qRGWeOX1448ezNpRnBbIfBSGsrO_t2q-6P_Ray7bnYiEa5lTkNRX5eBAYb-1mYCkUs_PV_OnjfVXg4hwUMfcRf0Pr80gwvh1JxZowW3YjIcujYKqBiH6W_EZe-zjuWlEdSr_2DAzDXyxyorNyDUXJKicGslMvi7yd21uRdsdkN2B8/s5896/06%20TH%202164%20VCF-VCA%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="5896" data-original-width="4434" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSD464eAGKItk_eI0qRGWeOX1448ezNpRnBbIfBSGsrO_t2q-6P_Ray7bnYiEa5lTkNRX5eBAYb-1mYCkUs_PV_OnjfVXg4hwUMfcRf0Pr80gwvh1JxZowW3YjIcujYKqBiH6W_EZe-zjuWlEdSr_2DAzDXyxyorNyDUXJKicGslMvi7yd21uRdsdkN2B8/s320/06%20TH%202164%20VCF-VCA%20cuts%20and%20wirebridges.jpg" width="241" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><span style="color: #fff2cc;">The VCA board has male pinheaders soldered directly to the copperside so the board connects to the filter board with the copperside facing the component side of the filter board.</span></div><div><span style="color: #fff2cc;">This is a bit fiddly to solder, especially because I used a double row of pinheaders to make sure the connections are solid. I used the same method I used with the wavetable oscillator. I put some solder down between the holes where the pins sit and I put some flux on the solder part of the pins and pre-soldered them too. Then I put them in place and I only needed to heat the solder already there to make them connect to the stripboard. Do this before you solder in any components so you have enough room to work and fit the two boards together regularly to make sure it all aligns like it should.&nbsp;</span></div><div><span style="color: #fff2cc;">Be careful not to overheat the pinheaders because the plastic that holds them together can melt. When I solder male pinheaders I always connect female connectors to them so the heat can dissipate</span><br /><div style="text-align: left;"><br /></div></div><div style="text-align: left;">Finally here's the Bill of Materials:</div><div style="text-align: left;">You can use other types of Schottky diodes if you want, like the BAT41 or 42, 43 etc. It doesn't matter as long as they are Schottky diodes.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEii6jbuc0lw9tp21p1H34d6UJq01b6FWzGcmELKAOuvhuCYoiweVlGuLqbmHOPAp12wksb3JUUjhQMf1sGX-E6OlD2KCWVSO4iZDnCJoAth-myhqOV7D8Bxmz38FjmZIp7GjujkxLi8ARF7TKiw9kly7CRpwXGU1Y7WMRvX1RMWky_hQyiE8HQU8kvxrERn/s1405/TH%202164%20VCF-VCA%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="531" data-original-width="1405" height="121" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEii6jbuc0lw9tp21p1H34d6UJq01b6FWzGcmELKAOuvhuCYoiweVlGuLqbmHOPAp12wksb3JUUjhQMf1sGX-E6OlD2KCWVSO4iZDnCJoAth-myhqOV7D8Bxmz38FjmZIp7GjujkxLi8ARF7TKiw9kly7CRpwXGU1Y7WMRvX1RMWky_hQyiE8HQU8kvxrERn/s320/TH%202164%20VCF-VCA%20BOM.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">PICTURES:</span></b></div><div style="text-align: left;">Here are some pictures from the build proces:</div><div style="text-align: left;">The stripboards with wirebridges installed:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghoXn0xSVV421CVKCLt-EZ3nSaty-Fa1pOyHu7abYholy_Uud0sdCCerLwLKUyZYb0UmX-VnfHoqcwRciwntv5xgrR0AD2_tKJ0XZmK_tZtAz3MaPPymrcZ873YKecbSt1NP3ZFS1Xx6_ADZ47VcwZGILym5VXQhHJQaF2ky9sbT2r8h6Fjk1RXiwkL9hu/s4000/20241130_132657.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghoXn0xSVV421CVKCLt-EZ3nSaty-Fa1pOyHu7abYholy_Uud0sdCCerLwLKUyZYb0UmX-VnfHoqcwRciwntv5xgrR0AD2_tKJ0XZmK_tZtAz3MaPPymrcZ873YKecbSt1NP3ZFS1Xx6_ADZ47VcwZGILym5VXQhHJQaF2ky9sbT2r8h6Fjk1RXiwkL9hu/s320/20241130_132657.jpg" width="320" /></a></div><div><br /></div>Here's how I soldered on the male pinheaders:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQKY11im_6eTAUdt98a61Ic5wceo_WsDyKWolVaA0jaPiieYlLi44dSMADeVEMXa96hyN0w4hFUNQpn3x7Kx4QkLN5oSTZYPcguckDSJnookTAh4UXVPTNEDzhlSY2W7Ljj2ni8C1sAPXTMco48Js5h8BT6crdzRVjgsGbuMNrXdrA_qa-kFFbYRUe-s7t/s4000/20241130_183209.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQKY11im_6eTAUdt98a61Ic5wceo_WsDyKWolVaA0jaPiieYlLi44dSMADeVEMXa96hyN0w4hFUNQpn3x7Kx4QkLN5oSTZYPcguckDSJnookTAh4UXVPTNEDzhlSY2W7Ljj2ni8C1sAPXTMco48Js5h8BT6crdzRVjgsGbuMNrXdrA_qa-kFFbYRUe-s7t/s320/20241130_183209.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPm_kk9GDDsQ2AsmTv4I4QUGCEZiivlpADTj41U4q_zWdhs5vEaJsH2525MlQj-_guYNSS2COHdJqkDbbjhNQn_HtZ1qqZWyLDiqAoukHkvopVS9wLMBRFfDWQHBWhYkfnEjfrnOdRRSLH0WPh2XfqwMueY_M2nRgMmZUxLXZofbHkmqtDLiJcBg5WgnO7/s4000/20241130_183259.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPm_kk9GDDsQ2AsmTv4I4QUGCEZiivlpADTj41U4q_zWdhs5vEaJsH2525MlQj-_guYNSS2COHdJqkDbbjhNQn_HtZ1qqZWyLDiqAoukHkvopVS9wLMBRFfDWQHBWhYkfnEjfrnOdRRSLH0WPh2XfqwMueY_M2nRgMmZUxLXZofbHkmqtDLiJcBg5WgnO7/s320/20241130_183259.jpg" width="320" /></a></div><div><br /></div>Both boards finished but without their chips. I only put those in at the last moment to prevent damaging them.</div><div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDwV4r5mlEVTz1ShunxnHolJTi0_29qlJWLWljb9uWrXXR5I51BO6zKSe55XcWDfHuNX78b7Gya4k9PGEBEKY0_Bg71Ff-NEy9daxXjOatURyh7gM93Xi3qSCgUB-m6PMa9USThpMz690Za7q5gAEvNqNPdd-WWkd3MmB49wqkCiUeNhX3PjBjWSOYHbHx/s4000/20241130_191018.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDwV4r5mlEVTz1ShunxnHolJTi0_29qlJWLWljb9uWrXXR5I51BO6zKSe55XcWDfHuNX78b7Gya4k9PGEBEKY0_Bg71Ff-NEy9daxXjOatURyh7gM93Xi3qSCgUB-m6PMa9USThpMz690Za7q5gAEvNqNPdd-WWkd3MmB49wqkCiUeNhX3PjBjWSOYHbHx/s320/20241130_191018.jpg" width="320" /></a></div><div><br /></div><div>The faceplate with the holes drilled in and de-burred, with the waterslide design applied to it. You can see there are still some bits that are not completely flat but when it is dry it will all be tight.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2_ao_ulctaX7Mt0Db5IPMk0UkheuUWJYGIx0-IZaWlQjKf9qvQ672drqP2IIaaH6OnvEiVI_O9-KVgC78TfMxPeyX2nFvcPpIgu-c4XSEEbUoRB_46dATRJTWqX9xSdVtIIZSjAOxh6bf-U1rpT18BpVMSJ_jxSLcselUEBo11Wca5vQIcNl-aOC6R8tp/s4000/20241202_155505.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2_ao_ulctaX7Mt0Db5IPMk0UkheuUWJYGIx0-IZaWlQjKf9qvQ672drqP2IIaaH6OnvEiVI_O9-KVgC78TfMxPeyX2nFvcPpIgu-c4XSEEbUoRB_46dATRJTWqX9xSdVtIIZSjAOxh6bf-U1rpT18BpVMSJ_jxSLcselUEBo11Wca5vQIcNl-aOC6R8tp/s320/20241202_155505.jpg" width="320" /></a></div><div><br /></div><div>As you can see in the picture below, it dried up beautifully. Now to cut out all the holes with a very sharp hobby knife and then give it a few more layers of clear lacquer.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyNI4wrkF_E12hz0PQZkdq1hRORxA6pz05DCOBkrddc_o_DBsJV-_gqCFbrVpWJgzA84jbJ0UtJKTpBb7dvTcldYsTdBRYwGJEq_IDqlWP2L0pG8MWKhDNfb_1Os_0rwwqV060f4wTqsTtB9enbfFfxvLVz4c51qZJVW_PfQDSM7tvfu8EeHC001o5DAol/s4000/20241202_165012.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyNI4wrkF_E12hz0PQZkdq1hRORxA6pz05DCOBkrddc_o_DBsJV-_gqCFbrVpWJgzA84jbJ0UtJKTpBb7dvTcldYsTdBRYwGJEq_IDqlWP2L0pG8MWKhDNfb_1Os_0rwwqV060f4wTqsTtB9enbfFfxvLVz4c51qZJVW_PfQDSM7tvfu8EeHC001o5DAol/s320/20241202_165012.jpg" width="180" /></a></div><div><br /></div><div>Here's the end result, not yet wired up. I put in two 3 CM M3 bolts with counter-sunk heads and screwed them tight with nylon ringed locknuts. Then I put some white paint over the heads and applied the waterslide paper overtop of that. It doesn't make the screw heads totally invisible but it works. I forgot to put in a hole for the 3mm LED. I later drilled one in just underneath the top text.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR_BsjRVOjX5ihRciL2JIH9GP1m29-6PgG7myjEsluA4QxtceEjbqTyY7Ob6lBDhgOR5PdwY1SVXMfnxPwNp81EP37jyDzIQsMd_x392QdoQEAUWgeY-EHIoY3qteDs6xk-76Cx5HXrUf-VtIotyJWT2mxf-HjWv7xB9bziM4SwNJAWH3OEfW5sCfSEIvs/s2704/Panel%20fully%20stocked.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2704" data-original-width="2132" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR_BsjRVOjX5ihRciL2JIH9GP1m29-6PgG7myjEsluA4QxtceEjbqTyY7Ob6lBDhgOR5PdwY1SVXMfnxPwNp81EP37jyDzIQsMd_x392QdoQEAUWgeY-EHIoY3qteDs6xk-76Cx5HXrUf-VtIotyJWT2mxf-HjWv7xB9bziM4SwNJAWH3OEfW5sCfSEIvs/s320/Panel%20fully%20stocked.jpg" width="252" /></a></div><div><br /></div>While I was waiting for some components to come in the mail I wired up the backside of the panel as far as I could. I connected all grounds together with one copper wire and I also soldered all the potmeter pins that needed to be grounded to that same wire. This way I will only need one ground wire going to the stripboard to ground everything. This is how I usually wire up ground connections. Do not rely solely on the metal of the faceplate to be the ground. Remember Aluminium oxidizes and oxides are not good at conducting current.</div><div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFkU10mWWAqJ8F3FcVRXuFthes5gfPTKeNNysNkI_xxFWKZ-sOkG58HVllGyidnrpzHCReAjHqyRkOx9DqvyDKiLauH7RCMlE05FP5zzD6eJqVAhmHhfXWcBZji6I5Wrql82kLneq8VgnrxpqsGQgWeqNlpcppECbDeA2Ei8I7lpnTCAVbmC4MiY_GcS02/s4000/Panel%20backside%20wired%20up.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="2252" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFkU10mWWAqJ8F3FcVRXuFthes5gfPTKeNNysNkI_xxFWKZ-sOkG58HVllGyidnrpzHCReAjHqyRkOx9DqvyDKiLauH7RCMlE05FP5zzD6eJqVAhmHhfXWcBZji6I5Wrql82kLneq8VgnrxpqsGQgWeqNlpcppECbDeA2Ei8I7lpnTCAVbmC4MiY_GcS02/s320/Panel%20backside%20wired%20up.jpg" width="180" /></a></div><br /><div style="text-align: left;">When all components were in, I wired it all up which took me almost a whole day and then I plugged it in and.... it didn't work at all. I tried to troubleshoot it, I posted in the Facebook group about it but it wouldn't work. Then I left it for two days and came back at it with fresh eyes on a sunday morning and I found the mistakes within half an hour. I made two little errors in the layout and I soldered one wire to the wrong place and I forgot to connect the ground copperwire, which has all the socket grounds and potmeter grounds connected to it, to the stripboard. After I corrected that, it all worked fine. Strangely enough the missing ground wire connection was something I noticed later on, but even without a ground connection everything worked! I was really surprised by that.&nbsp;&nbsp;</div></div><div style="text-align: left;"><span style="color: #fff2cc;">Btw, I normalled the lowpass output of the filter to the input of the VCA&nbsp;</span>so the filter output is automatically enterred into the VCA. To replicate this all you have to do is solder a wire to the audio output of the VCF and then solder the other end to the switch connection of the audio input socket of the VCA. When no patch-cable is connected to the VCA audio input, it gets its audio from the VCF output. If you connect a cable to the VCA input that VCF connection is broken.</div><div style="text-align: left;">Here's a look at the finished module:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhi-GBKU-BjA06u6WO_mNEaQCyKsfgeO-e0ITfsjHzbAvURar94qRpoYT5_StS-18VwS3QYGoI6M6Iq3duLse6ikJkA75ctTiYCn1PYe-FoD1uyBCaTF7hTurPAzaCRLs8oPceUGBHd9k3enYorlCmiJykf8o5QsFrHdKPj9bMXc3jEm55acdaI2dZsWzQM/s4000/Finished%20module-01.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhi-GBKU-BjA06u6WO_mNEaQCyKsfgeO-e0ITfsjHzbAvURar94qRpoYT5_StS-18VwS3QYGoI6M6Iq3duLse6ikJkA75ctTiYCn1PYe-FoD1uyBCaTF7hTurPAzaCRLs8oPceUGBHd9k3enYorlCmiJykf8o5QsFrHdKPj9bMXc3jEm55acdaI2dZsWzQM/s320/Finished%20module-01.jpg" width="320" /></a></div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9ZM37E5w5DDMOfkba-0sjHVThdVAP8nhI5XzgE8eY0BmwzLhtbjdxckbtE75CebDAJGXNkRI5Y4sErvBsaf8mcbMJgYlj-BJ7cKqiIVXYPshn32jBbYnjnKrGjANQilJtkqMVRbHfz66m-y5h1ZIFfHgkzQ0GyojUz_87O4NiGN8vG2_SaID18msNFjA0/s4000/Finished%20module-02.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9ZM37E5w5DDMOfkba-0sjHVThdVAP8nhI5XzgE8eY0BmwzLhtbjdxckbtE75CebDAJGXNkRI5Y4sErvBsaf8mcbMJgYlj-BJ7cKqiIVXYPshn32jBbYnjnKrGjANQilJtkqMVRbHfz66m-y5h1ZIFfHgkzQ0GyojUz_87O4NiGN8vG2_SaID18msNFjA0/s320/Finished%20module-02.jpg" width="320" /></a></div><div><br /></div><div>As you can see, the boards bend back a little because they are only connected to the panel at one end and there are a lot of wires pushing it up. To pull the other side down, I soldered a wire from the socket ground to the ground of the eurorack powerheader. These points are directly above eachother and the copper wire now pulls the boards down which looks better and helps keep the depth to a minimum. It also takes care of grounding everything on the panel.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuhUrkJ_Z0ZHGLMWTO2Z6ZoDkfJdJ5JyeSaV2GXr37RGEbVKpIve1GyCfe1D7Iv_HQ9CZuh5yOON0RauhzkJPbAQfm2eLtLrZOifbfbLoB_io83foIjPjp9Re78X3AsXnoTw51bpjlz5UoXG9NkB1YjyZRbRHHINHnpyBVyxJ5Q6hyphenhyphenBjgfQYoRH2VoCTnc/s4000/2164%20boards.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuhUrkJ_Z0ZHGLMWTO2Z6ZoDkfJdJ5JyeSaV2GXr37RGEbVKpIve1GyCfe1D7Iv_HQ9CZuh5yOON0RauhzkJPbAQfm2eLtLrZOifbfbLoB_io83foIjPjp9Re78X3AsXnoTw51bpjlz5UoXG9NkB1YjyZRbRHHINHnpyBVyxJ5Q6hyphenhyphenBjgfQYoRH2VoCTnc/s320/2164%20boards.jpg" width="240" /></a></div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj29PBS8jPir9HmXsZI_R7TBdnmixIdt3_E3jPnCUIFOyGXyViRwgIhmKGE7IuvTI2WlhJl7dPTBrcOs9ZsujEF0pgJ4QihZH2V9fFAcG4j45Oqj2ku3sjlxrPEDnDxlDehzhmx7r9F3t3iPo-wJHkv0wAQOJuxlEqwuMr-EPdOvJ36l9un_ChuFfwlf1QM/s4000/2164%20boards-1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj29PBS8jPir9HmXsZI_R7TBdnmixIdt3_E3jPnCUIFOyGXyViRwgIhmKGE7IuvTI2WlhJl7dPTBrcOs9ZsujEF0pgJ4QihZH2V9fFAcG4j45Oqj2ku3sjlxrPEDnDxlDehzhmx7r9F3t3iPo-wJHkv0wAQOJuxlEqwuMr-EPdOvJ36l9un_ChuFfwlf1QM/s320/2164%20boards-1.jpg" width="320" /></a></div><div><br /></div><div>It is still a pretty deep module. It's 47mm deep. But it will fit most eurorack cases like the Nifty Case just fine.&nbsp;</div><div><br /></div><div><b><span style="color: red;">VIDEO:</span></b></div><div>Here's a cool demo video I found on YouTube by Fonitronik:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/GvGTFL0KBVw" width="320" youtube-src-id="GvGTFL0KBVw"></iframe></div><br /><div><b><span style="color: red;">A few final notes:</span></b></div><div>I based my panel design on the original Fonitroniks panel and the labeling on that is somewhat different than on the schematic. This caused me some confusion as I only really noticed it after I had finished the panel. For instance the DC IN on the VCA is actually an extra audio input that can also take CV signals. The Linear AM on the schematic is labelled Lin. FM on the original panel. So I would advise you to keep to the labeling of the schematic and the layouts and not use the Fonitroniks panel as inspiration, like I did.</div><div><br /></div><div>Here is the original panel of the Eurorack module:</div><div>Note how it says Linear FM at the bottom right input but with a VCA the control voltage influences the amplitude or volume of the output, not the frequency. So it should be AM.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2aq6BWlQlejEeZwFJblp93zm5-KUs2W_IsUi57ih8tSS79yXwfmLctrJYJ3SuJX3VR4e1ojryqYJm3rrfSFGh2CYEz1QajSJZr-jT_Z4rb-rvwkxXFcsR3K6RzVCZ8_6z_zugrD9d8I1n8nO2cqKzdro_sp3UDbenDJlsNI1cLs5_r5RJjzaQ0HXVo_fD/s805/Panel%20design%20original%20Fonitronik.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="805" data-original-width="507" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2aq6BWlQlejEeZwFJblp93zm5-KUs2W_IsUi57ih8tSS79yXwfmLctrJYJ3SuJX3VR4e1ojryqYJm3rrfSFGh2CYEz1QajSJZr-jT_Z4rb-rvwkxXFcsR3K6RzVCZ8_6z_zugrD9d8I1n8nO2cqKzdro_sp3UDbenDJlsNI1cLs5_r5RJjzaQ0HXVo_fD/s320/Panel%20design%20original%20Fonitronik.JPG" width="202" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Here's an explanation of the input options of the panel design above. They can be very confusing.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2zuymU7RfJHJ2vYns9DNr2cIsz87S6GYzRScpv9nEkR4KhSlxI-wQ_0VSuW8_LX6sSIbtI70iO8J87ElsmeKDvg_QkL-e53y4Ofz7iZ3KvN3mqnr-6qIrKYJ912vF2bdHEd-_35FUjmEY07cFYWx_y-ggK0dLubV1DoLMEtr6eA8crGpVskJheo44DsJR/s2033/2164%20VCF%20VCA%20frontpanel%20explanation.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1673" data-original-width="2033" height="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2zuymU7RfJHJ2vYns9DNr2cIsz87S6GYzRScpv9nEkR4KhSlxI-wQ_0VSuW8_LX6sSIbtI70iO8J87ElsmeKDvg_QkL-e53y4Ofz7iZ3KvN3mqnr-6qIrKYJ912vF2bdHEd-_35FUjmEY07cFYWx_y-ggK0dLubV1DoLMEtr6eA8crGpVskJheo44DsJR/s320/2164%20VCF%20VCA%20frontpanel%20explanation.jpg" width="320" /></a></div><br /><div>I took my panel design and added more understandable labels. It used to look like the design above here but I think this will make more sense. There's four designs for an A-4 sized waterslide paper so you have some spares should you mess up. I also added a place for the LED which is connected to the filter CV-1 input (that's the envelope input for the filter). This image is to scale for a 14hp Eurorack panel. You can save it and print it out onto waterslide paper and use it to make you panel. Use a normal paper printout as your drill guide. I put in dots where the holes need to be drilled.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2A09gDEBOo1SrC3EkM5sgYw9AR8Szwyy2ufropDOQCGbPkKK8tZQfiYNTniL1PhMIIMnAvN27qwqYBZK7NMnmyMoeeXchELQDU5ICsdO7uFtErBbu_pB3AyA7YWQG-f_ilykEktYko8nzK0bf7xx-QVSqmqFjcjvNlCE6rGMb2R_Yd2crx4gDIQa_QaD-/s3496/2164%20VCF%20VCA%20frontpanel%20design%204x.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3496" data-original-width="2480" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2A09gDEBOo1SrC3EkM5sgYw9AR8Szwyy2ufropDOQCGbPkKK8tZQfiYNTniL1PhMIIMnAvN27qwqYBZK7NMnmyMoeeXchELQDU5ICsdO7uFtErBbu_pB3AyA7YWQG-f_ilykEktYko8nzK0bf7xx-QVSqmqFjcjvNlCE6rGMb2R_Yd2crx4gDIQa_QaD-/s320/2164%20VCF%20VCA%20frontpanel%20design%204x.jpg" width="227" /></a></div><div><br /></div><div>Okay, that's it for this one.</div><div>If you have any questions or remarks about this project then please put them in the comments below. Comments are moderated and don't appear until I approved them which can take a while if you're in a different timezone than me. You can also post questions or show your work in the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook group</a> for this website.</div><div><br /></div><div><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-5529136830463965591
title: Synthesizer Build part-63: FASTEST ADSR IN THE WEST by Rene Schmitz.
author: Eddy Bergman
url: https://www.eddybergman.com/2024/12/ADSR%20Rene%20Schmitz.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">The fastest ADSR in the West. A simple to build and fully featured Envelope Generator. I thought it was about time for another ADSR project for the website and this one worked out great and it has no trimmers to set. I even added a few extra's to make it even better.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">This is an other 7555 based envelope generator like the YuSynth one from project 24. Some people seem to have problems with that one so that's why I choose to do this project now.</div><div style="text-align: left;"><span style="color: #fcff01;">This ADSR will work on both +/-15V and +/-12V.</span> At +/-12V the maximum envelope amplitude is just under 8 Volt. If you run it on +/-15V the peak envelope value will be 10 Volt. It's a very fast Envelope Generator. The minimum risetime of the signal is 1mSec or 1/1000th of a second.</div><div style="text-align: left;">Now this is roughly the same setup as in the previous 7555 ADSR from project 24 but it does work a lot better, especially when using Schottky diodes. The whole problem with the DC offset voltage left on the ADSR output comes down to the forward voltage drop of the diodes. That's why Schottky's are so useful because they have only a third of the voltage drop of silicone diodes. Now what would be even better is to have diodes with no voltage drop.&nbsp;</div><div style="text-align: left;">To achieve that we have to put the diodes inside the feedback loop of an opamp. That's what happens in the <a href="https://kassu2000.blogspot.com/2015/05/precision-adsr.html?utm_source=chatgpt.com" target="_blank">Kassutronics Precision ADSR</a> which I recently also added to the website as <a href="https://www.eddybergman.com/2025/04/Kassutronic-precision-adsr.html" target="_blank">project number 67</a>.</div><div style="text-align: left;"><span style="color: #fff2cc;">So this ADSR and the Yusynth 7555 ADSR have become a bit obsolete now, eventhough they work just fine for use with VCA's and for Filter CV signals. I would advise anyone wanting to build an ADSR to go to project 67 and build that one.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">Here is the schematic for this circuit. I've redrawn it from the sketch posted on <a href="https://www.schmitzbits.de/adsr.html" target="_blank">Rene Schmitz website</a>.</div><div style="text-align: left;">The opamps are numbered in the order they are used on the stripboard. All diodes have been replaced with Schottky diodes which work much better in this circuit.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuuzdqcAIoMmCpCpbraKYWOTEfm97acm8cgxQM5c1jv9JgcEXJLG_fDb1-lz_7KC2C4VBcjAtAkBCEsRxNfLjJJBZjDoF4-T8kYqYHWNPReqKQbz7jOqJhrRRUz62u8jLgSJJ_q1lB85rhB824PvBL0PaUVQttyzuexgR5KawSChQwzEp3KOmMbjeJzm_2/s5905/Fastest%20ADSR%20in%20the%20West%20schematic%20w%20schottky.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3197" data-original-width="5905" height="173" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuuzdqcAIoMmCpCpbraKYWOTEfm97acm8cgxQM5c1jv9JgcEXJLG_fDb1-lz_7KC2C4VBcjAtAkBCEsRxNfLjJJBZjDoF4-T8kYqYHWNPReqKQbz7jOqJhrRRUz62u8jLgSJJ_q1lB85rhB824PvBL0PaUVQttyzuexgR5KawSChQwzEp3KOmMbjeJzm_2/s320/Fastest%20ADSR%20in%20the%20West%20schematic%20w%20schottky.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Click here for a <a href="https://tinyurl.com/22xe8obh" target="_blank">FALSTAD SIMMULATION</a> of this circuit.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I've added some extra's to this design. The original design only uses two opamps but I wanted to include a LED and also an inverted output so I decided to use a quad opamp, the TL074, and include an attenuverted output where you can have in inverted envelope signal with the potmeter turned fully counter clockwise, attenuation with zero signal when the potmeter is at the 12 o'clock position and a normal envelope when the potmeter is turned fully clockwise. I took the design from the AD/AR attenuverter mod from Ole Stavnshoej design (project 44). This is a great option to have when you use the ADSR with a filter. Turning the attenuverter will give the filter some very cool resonance response.</div><div style="text-align: left;">I decided to adapt the design to more run of the mill parts, like for instance I used 1M potmeters instead of the 2M2 ones in the original schematic. I changed the 220 Ω resistors to 100 Ω types and the capacitor from 2µ2 to 4µ7 to keep the original timebase intact. This is all explained in the text underneath the original schematic on the Schmitzbits website.</div><div style="text-align: left;">The circuit is relatively simple so I was able to build it up on a very eurorack friendly sized piece of stripboard. It's only 21 strips by 33 holes. Although I left the V,W and X strips on the board, they are not populated. You can use them to connect L brackets to mount the board to a panel. The three transistors on the Gate input represent the same setup as we've seen before in the Yusynth 7555 ADSR only there he had no resistors at the base of transistors 2 and 3. It works as follows: the first two transistors make up a schmitt trigger which turns any input signal into a sharp gate signal. That signal now goes through a capacitor that turns any long gate signal into a short pulse. That pulse is inverted in the third transistor stage to make it acceptable for the 7555 chip, going in at pin 2.&nbsp;</div><div style="text-align: left;">Once the ADSR has been triggered the sustain level for that cycle is frozen. You can not add sustain while the ADSR is in its cycle, unlike the Digisound ADSR which can do this. Not that that's important. it's just something I noticed while testing the circuit.</div><div style="text-align: left;"><span style="color: #fff2cc;">The 1M resistor, in red on the schematic and in purple on the layouts below, can be added to provide for some input hysteresis. This will improve triggering on slowly changing waveforms. In the layout below, the purple 1M resistor on the left indicates where it should go if you want to include it. I left it out. Only include it if you really think you're going to need it. If in doubt, Leave it out.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Here are the layouts I made for this project. As always they are verified. I used them to build my module. It's important to use logarithmic 1M potmeters for Attack, Decay and Release. The time based parameters. Otherwise it will be much more difficult to set these parameters accurately. It will work with linear types but get logarithmic pots for these. Sustain is a level control so that can and should be a 10K linear type potmeter.</div><div style="text-align: left;">I used Schottky diodes throughout this design because with 1N4148 diodes there's a DC offset voltage present on the output. Using Schottky diodes helps to prevent that.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Wiring diagram:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEIKus9A4fSI4o1nNeiWPHHsoYGp-UKTO0B4z6LW42F73s_wUFQ4F-ErUSFCIaQfU3V4fgmNavwRjN22riXAI5oKtnBDgCUcnkhDjrvq8CncTm0tlsRZIBzd7OWJ33wsMZnM43umoQdLO2ybC5oO-iNVMiQSnuBWWzzxaEHQjThUyXG1UKfgP199h66NA5/s7313/01%20Fastest%20ADSR%20v3%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4747" data-original-width="7313" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEIKus9A4fSI4o1nNeiWPHHsoYGp-UKTO0B4z6LW42F73s_wUFQ4F-ErUSFCIaQfU3V4fgmNavwRjN22riXAI5oKtnBDgCUcnkhDjrvq8CncTm0tlsRZIBzd7OWJ33wsMZnM43umoQdLO2ybC5oO-iNVMiQSnuBWWzzxaEHQjThUyXG1UKfgP199h66NA5/s320/01%20Fastest%20ADSR%20v3%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">Stripboard only:</div><div style="text-align: left;">Again, leave out the purple 1M resistor unless you're going to feed this ADSR with slowly changing Gate input signals. Not likely so leave it out.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9MirOFV0bumTfCx9FzwAL1Ka5-4agvqswVs-0M76sEdiJxDT8lfBgXnEVQPKXMKeqorqDZ0aBdUgXqQJjxSFzy_3J4NXAX_cfeI_MxLUjrLRxZhTrq4tbLV66zfWZD7qBZQMcWrNnsw7NR0KJIRHsq4vsK-ajVJQSMG9joQFNWLmzHzMH59P2QWNBFM6j/s3985/02%20Fastest%20ADSR%20v3%20-%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2791" data-original-width="3985" height="224" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9MirOFV0bumTfCx9FzwAL1Ka5-4agvqswVs-0M76sEdiJxDT8lfBgXnEVQPKXMKeqorqDZ0aBdUgXqQJjxSFzy_3J4NXAX_cfeI_MxLUjrLRxZhTrq4tbLV66zfWZD7qBZQMcWrNnsw7NR0KJIRHsq4vsK-ajVJQSMG9joQFNWLmzHzMH59P2QWNBFM6j/s320/02%20Fastest%20ADSR%20v3%20-%20stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Cuts and wirebridges seen from the component side. You know the drill by now; mark the cuts on the component side with a Sharpie or Edding pen and then stick a pin through the marked holes and mark them again on the copper side. Then cut at the marked places with a sharp, hand held, 6- or 7mm drill bit.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKIwjHjOsnrwkY2cK6z3EdYEIadOBqMs76VEG-iGc-wCwesry2fBQEP3W6_FOvgrl6fqrHyrUvXu6i19HQFtvXF08zIbDNVCvHEJOxec7xPhzkfvALsiOYaPjlT6rOk3XkK5Hkt108MmJbTu4VEElp2pfvL9LqXk_4Nxy0514yrnnKbkXinj8Q7bDptZMp/s3816/03%20RS%20ADSR%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3080" data-original-width="3816" height="258" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKIwjHjOsnrwkY2cK6z3EdYEIadOBqMs76VEG-iGc-wCwesry2fBQEP3W6_FOvgrl6fqrHyrUvXu6i19HQFtvXF08zIbDNVCvHEJOxec7xPhzkfvALsiOYaPjlT6rOk3XkK5Hkt108MmJbTu4VEElp2pfvL9LqXk_4Nxy0514yrnnKbkXinj8Q7bDptZMp/s320/03%20RS%20ADSR%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Here is the Bill of Materials. <span>I altered the diode types to Schottky diodes because they will work much better in this design. I put in the BAT4* series (like: BAT41, BAT42, BAT43 etc) because they work really well and have good availability in webshops. Any Schottky diode will do though.</span></div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixemkaJs2U0O1YZLo1sctPuJVUkynrd3Dk34F91i3lQYGxBgvWxbKMzsBwMeXy0x5b4xyBwf3jvPPS5EqMDM5elKXApyCVz6WKrnwIzObIgnxhrGdkeXHOcRlAGoi_7SQlehXpEqvA3Y6Gj2ncjgxT0ABb1cnAqPTzKRRZmgFEvy5Q-B_iAaPYEzPoSQOk/s614/RS%20ADSR%20-%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="377" data-original-width="614" height="196" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixemkaJs2U0O1YZLo1sctPuJVUkynrd3Dk34F91i3lQYGxBgvWxbKMzsBwMeXy0x5b4xyBwf3jvPPS5EqMDM5elKXApyCVz6WKrnwIzObIgnxhrGdkeXHOcRlAGoi_7SQlehXpEqvA3Y6Gj2ncjgxT0ABb1cnAqPTzKRRZmgFEvy5Q-B_iAaPYEzPoSQOk/s320/RS%20ADSR%20-%20BOM.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><b><span style="color: red;">OSCILLOSCOPE IMAGES:</span></b></div>Here are some screen shots from my oscilloscope to give you an impression of what the signal looks like. All testing was done with a +/-12V powersupply:<br /><div class="separator" style="clear: both; text-align: center;"><br /></div>Here's the normal envelope output. The envelope signal does have a small positive offset voltage of 400mV I noticed. But this won't cause any VCA to stay open so it's of no consequence.&nbsp;<div>However I changed the diodes for Attack and Release into Schottky diodes and that reduced the offset to just 16mV (16 thousandth of a volt) which is the same as 0V to me. The offset voltage is the result of the fact that the 4.7µF cap has to discharge through a diode and a diode has a voltage drop over it of about 0.6V (with silicon diodes). So the lower that voltage drop the better. With Schottky diodes the voltage drop is only about 0.2V which allows the cap to discharge as good as fully.<br /><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgykGbT6e8hfKn63U2zOLz5dQutOrSd5mgJOP3HA3oB4VeCT73sukHbJfh4manU5u9rrByqf3SiAOCVdnwngNjXl1WIhD0xMuUl_fsPPkp2cxrOhdut7gnrq7kmqPeKoZkccqV3OVjm2ikBS2U0Z6TBuFmdYwYIpZkBRhvlQqCh2KBn1boU3YMLSTJgNByA/s800/01%20Envelope%20signal.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgykGbT6e8hfKn63U2zOLz5dQutOrSd5mgJOP3HA3oB4VeCT73sukHbJfh4manU5u9rrByqf3SiAOCVdnwngNjXl1WIhD0xMuUl_fsPPkp2cxrOhdut7gnrq7kmqPeKoZkccqV3OVjm2ikBS2U0Z6TBuFmdYwYIpZkBRhvlQqCh2KBn1boU3YMLSTJgNByA/s320/01%20Envelope%20signal.jpg" width="320" /></a></div><div><br /></div><div>Here's the normal output in yellow and the inverted in blue coming from the attenuverter mod I added on myself. It works like a charm.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipEcVZJSDz7FQXr8BphgT1HGQegNez72Dbem7uMVmnfGw9v-mX_jLNpLEMkN-KwJHFCd1RMe8rE7rsPc-UdObrBg_sM0acc6CyXWsvK59aj_gglZmaQK5wgumsxW-23rHX3oXklvPwKU5PVtZpj3bQHewpTHTVSMBoKdR1AKmoQIPDObHsCPJEZ2m_0hQr/s800/02%20Normal%20and%20Inverted%20signal.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipEcVZJSDz7FQXr8BphgT1HGQegNez72Dbem7uMVmnfGw9v-mX_jLNpLEMkN-KwJHFCd1RMe8rE7rsPc-UdObrBg_sM0acc6CyXWsvK59aj_gglZmaQK5wgumsxW-23rHX3oXklvPwKU5PVtZpj3bQHewpTHTVSMBoKdR1AKmoQIPDObHsCPJEZ2m_0hQr/s320/02%20Normal%20and%20Inverted%20signal.jpg" width="320" /></a></div><div><br /></div><div>Here you can see, in the blue trace, the attenuverter in action. I'm turning the potmeter as the trace goes from left to right.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrvMZQabEb5lpp0bIXjMPxF7lePyh6ScPMtH5xU5Ic7OUJYEsBvbN_X5Rr_NMdc377BOkOO8Y7UPiRqJEyK4EcbXuM9j86rneoX3zf-PjI5evfw4oaW_522EM2-DM4zzFuKm8sWFRVayf8_8s8kJBxqoxUCPzVCJ9orVxy-CBKVwcTMixnUMUEJK1J2mmW/s800/04%20Turning%20the%20attenuverter%20up-2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrvMZQabEb5lpp0bIXjMPxF7lePyh6ScPMtH5xU5Ic7OUJYEsBvbN_X5Rr_NMdc377BOkOO8Y7UPiRqJEyK4EcbXuM9j86rneoX3zf-PjI5evfw4oaW_522EM2-DM4zzFuKm8sWFRVayf8_8s8kJBxqoxUCPzVCJ9orVxy-CBKVwcTMixnUMUEJK1J2mmW/s320/04%20Turning%20the%20attenuverter%20up-2.jpg" width="320" /></a></div><div><br /></div><div>This is the signal at a pretty high rate at almost 3Hz. No problem for this ADSR.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgq4TtHohoYPYiIBIdvujFCy8M0diTKsw_FFnhiw4ftIsP19jsGcWih88eMJAF7ZrL84VNgWSCAb7pNT4mojuHQVztxP7QdP4zcMHg_48HyHsdURd-FH-gIbIaOXyI_bPOSUVYtYzRxK74unSnHaZajovmjSnnCstFfnsDiHEShjZU_HbRkWUDnjDbudwQ8/s800/05%20High%20rate%20signal.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgq4TtHohoYPYiIBIdvujFCy8M0diTKsw_FFnhiw4ftIsP19jsGcWih88eMJAF7ZrL84VNgWSCAb7pNT4mojuHQVztxP7QdP4zcMHg_48HyHsdURd-FH-gIbIaOXyI_bPOSUVYtYzRxK74unSnHaZajovmjSnnCstFfnsDiHEShjZU_HbRkWUDnjDbudwQ8/s320/05%20High%20rate%20signal.jpg" width="320" /></a></div><div><br /></div><div>In yellow you can see the pulse as it comes out of the third transistor and into pin 2 of the 7555. It's a inverted pulse, triggered by the gate signal, that starts the ADSR.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdIf49lAOXhzFXh2Ou2XwpVcXw_wZ4YTBAwZLP2cWT8h6xphCg2ur5QduJN3Yq0rNz53VVtKscT975WgjgnZyB-WN-qHdpxWeiHby0CxeRO0O-Kq7vipGVDzxaZKPMsbrzJIZKwGeOQTVUbvNl7RwvejuHTFMamYNa6c6TDTJJn_VSBSoerAMqfIyX5WqR/s800/06%20The%20pulse%20on%20pin%202%20of%20the%207555.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdIf49lAOXhzFXh2Ou2XwpVcXw_wZ4YTBAwZLP2cWT8h6xphCg2ur5QduJN3Yq0rNz53VVtKscT975WgjgnZyB-WN-qHdpxWeiHby0CxeRO0O-Kq7vipGVDzxaZKPMsbrzJIZKwGeOQTVUbvNl7RwvejuHTFMamYNa6c6TDTJJn_VSBSoerAMqfIyX5WqR/s320/06%20The%20pulse%20on%20pin%202%20of%20the%207555.jpg" width="320" /></a></div><div><br /></div><div>This time the yellow trace is the gate signal at the input. This was measured after the 10K input resistor. The gate signal was a +/-5V pulse wave from an LFO.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimHxBvun7MBiCoSrMOFgiuY21Lg7RtSTudiO_RscZneFlbpllNXFY98G-o8lxtUjB8uNLHA0mOCA7VmY_sTS5gAmtc-M6C76-luLYuj9w0VKcMzOQiL6cYasFu5BAci_8omxd1TI9P1PO6SdtiuiKGNw2MYSdiHkJoPcLOgPQEhJK4-u_BxtRdI1KCLLzM/s800/07%20Gate%20signal%20low%20amplitude.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimHxBvun7MBiCoSrMOFgiuY21Lg7RtSTudiO_RscZneFlbpllNXFY98G-o8lxtUjB8uNLHA0mOCA7VmY_sTS5gAmtc-M6C76-luLYuj9w0VKcMzOQiL6cYasFu5BAci_8omxd1TI9P1PO6SdtiuiKGNw2MYSdiHkJoPcLOgPQEhJK4-u_BxtRdI1KCLLzM/s320/07%20Gate%20signal%20low%20amplitude.jpg" width="320" /></a></div><div><div class="separator" style="clear: both; text-align: center;"><br /></div></div><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures from the build proces.</div><div>Stripboard with cuts and wirebridges done.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjj_avcjby_3Ah0yfPRcCnGEZHqrhJ0rOGgM3RNalhLeMW1qRtpN0ebPQxaqJBzlGE14uRRB3SvKL5Rum5DmdnaG1Mh3lkN7_yNqIp7mMm0kAT6SRhmi7W1zsuyORYDJeQH-MlJhtfDDgTE7s7nlPqOFef9C3afPegxAzFj5KysKWTB6rL2C75ucWIN6k6X/s2956/Cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1796" data-original-width="2956" height="194" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjj_avcjby_3Ah0yfPRcCnGEZHqrhJ0rOGgM3RNalhLeMW1qRtpN0ebPQxaqJBzlGE14uRRB3SvKL5Rum5DmdnaG1Mh3lkN7_yNqIp7mMm0kAT6SRhmi7W1zsuyORYDJeQH-MlJhtfDDgTE7s7nlPqOFef9C3afPegxAzFj5KysKWTB6rL2C75ucWIN6k6X/s320/Cuts%20and%20wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>Finished stripboard ready for wiring up.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFZNE6aox3faH7CsLxh3dkmpX20E4-sF_TrGghLsP3o3Vs-Ev37fYdPT7CV1b2QTdRCkKSYRRmBbX0XcJYOryYZdXOgEVWSLeHH8hHILGlSoG80eFIMd95RcrRt3aZgPZ8dtpnu-GtMWSojsnIxmUB893ahdrl8wIMVx1kvqrWvp4WLeq1WfUtwtVA3xzO/s4000/ADSR%20Stripboard%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFZNE6aox3faH7CsLxh3dkmpX20E4-sF_TrGghLsP3o3Vs-Ev37fYdPT7CV1b2QTdRCkKSYRRmBbX0XcJYOryYZdXOgEVWSLeHH8hHILGlSoG80eFIMd95RcrRt3aZgPZ8dtpnu-GtMWSojsnIxmUB893ahdrl8wIMVx1kvqrWvp4WLeq1WfUtwtVA3xzO/s320/ADSR%20Stripboard%20finished.jpg" width="320" /></a></div><br /><div>All wired up ready for testing</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7rMDd2AXAUIh-LhGMltU7uN4nSPa9eN3Sdt8qOSsDCTs6qQ-iEyZs_u1HBrqzMHoZT_DiTHMb-jsN99z0-qOQ-8_6atRZmSfCdKrZ7oepFEzZsbLbrNjYiee8xFEqwgM66ghmXHZlK39y9R8uByHy9EGY5ZcwRB7Crtyvy6-zmrnFnZajqMHb0WwBdmor/s4000/Stripboard%20wired%20up.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7rMDd2AXAUIh-LhGMltU7uN4nSPa9eN3Sdt8qOSsDCTs6qQ-iEyZs_u1HBrqzMHoZT_DiTHMb-jsN99z0-qOQ-8_6atRZmSfCdKrZ7oepFEzZsbLbrNjYiee8xFEqwgM66ghmXHZlK39y9R8uByHy9EGY5ZcwRB7Crtyvy6-zmrnFnZajqMHb0WwBdmor/s320/Stripboard%20wired%20up.jpg" width="320" /></a></div><div><br /></div><div>I decided to use this ADSR for my DIY Kosmo synth and not for Eurorack so I took the YuSynth ADSR and replaced the stripboard with this one. I had to widen one hole to fit the attenuverter potmeter to which I added a bi-coloured LED to fill up another hole where a switch had been. I used a 4K7 resistor to connect it to the attenuverted output socket. I also re-used the manual trigger button that was already present in the panel. I took two 47K resistors and made a voltage divider so when I press the manual trigger it sends 7.5V to the gate input. (My DIY synth runs on +/-15V mostly).</div><div>Backview of the panel:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWpve4jnOfSyO_JeEGNtsg3A1voxb8m2k7mMtDbkO71IuRLinMfp4JllUcM5LHT0hHZ0-5yCpfdiEa6oXl3nFECIkRRzvR2qkyRRL_dB8muiL345mBkEciCml0Z6I_OUdIn8nzIFlks5mR699FTZ2OzW1JGzNxLO69wNmSxbDjhUBJI-5oSgr39Utg3xtb/s3868/Back%20view.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3868" data-original-width="2024" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWpve4jnOfSyO_JeEGNtsg3A1voxb8m2k7mMtDbkO71IuRLinMfp4JllUcM5LHT0hHZ0-5yCpfdiEa6oXl3nFECIkRRzvR2qkyRRL_dB8muiL345mBkEciCml0Z6I_OUdIn8nzIFlks5mR699FTZ2OzW1JGzNxLO69wNmSxbDjhUBJI-5oSgr39Utg3xtb/s320/Back%20view.jpg" width="167" /></a></div><div><br /></div><div>Here's what it now looks like mounted into the synth. My ADSR module has two Gate inputs each with a Schottky diode in series with the socket (soldered straight to the socket). This is to prevent +7.5V entering the Gate socket when I push the manual trigger button.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXs4POxfVpjYdRm-4w3594deXIrZ7aPMO6E8hmxTVbN86e_nRw70ndMgL0OR97575xL275Geh_9z6L3JU6AjwBSxMwetcC93MHKVp58wBhSUxG9ifNRKg9JCSaScLOg6rrNGNdCVj6kePKHvDxFTwk9TlcCcD665Kh6VT65FvNgJbQLOQ99jU4tlIChNxR/s3100/Buitin%20to%20synth.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3100" data-original-width="1953" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXs4POxfVpjYdRm-4w3594deXIrZ7aPMO6E8hmxTVbN86e_nRw70ndMgL0OR97575xL275Geh_9z6L3JU6AjwBSxMwetcC93MHKVp58wBhSUxG9ifNRKg9JCSaScLOg6rrNGNdCVj6kePKHvDxFTwk9TlcCcD665Kh6VT65FvNgJbQLOQ99jU4tlIChNxR/s320/Buitin%20to%20synth.jpg" width="202" /></a></div><br /><div>Luckily I could re-use the potmeters, which were 1M logarithmic types with a 10K linear pot for the sustain, the same as in this project.</div><div>You can see the blue LED underneath the attenuverter potmeter. The hole I had to fill up was 6mm and this LED is only 3mm so I used hotglue and made a sort of white blob that lights up red or blue. Worked out pretty well :)</div><div>I kept the dual gate inputs from my previous ADSR because I think it's handy to have. The gate inputs have Schottky diodes on them so that when I push the manual trigger button I don't get 7,5 Volt pushed into the gate patch cable(s). It's a safety feature I advise you to copy if you are going to include a manual trigger button.</div><div><span style="color: red;">Troubleshooting tip:</span> If your Decay and Sustain are not working then the most likely cause will be a broken Sustain potmeter. It happend to me when I built it into the panel I used for the YuSynth 7555 ADSR and it turned out it had a broken Sustain potmeter all the time.</div><br /><div><b><span style="color: red;">DEMO:</span></b></div><div>Here's a video I found on YouTube of someone demonstrating this ADSR in action. He's using it on the cutoff of a lowpass filter. Sounds pretty sweet. If he had the version with my attenuverter mod it would have sounded even better LOL ;)&nbsp;</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/J3iWH0vNEqs" width="320" youtube-src-id="J3iWH0vNEqs"></iframe></div><br /><div><br /></div><div>So that's another one done. I thought it was about time for a new ADSR project on this website, especially since some people seem to have problems getting the YuSynth 7555 ADSR of project 24 to work right. That's weird though because I always rated that one as near perfect but I think this will make an excellent alternative especially with the extra's I added. I'm really chuffed that it worked so well. Okay, I hope you will enjoy building this one.&nbsp;</div><div><br /></div><div>If you have any questions or comments about this project then please post them in the comments below of on the special <a href="https://www.facebook.com/groups/325860521842129" target="_blank">Facebook group</a> for this website.</div><div><br /></div><div><br /></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-4274512570907658582
title: Synthesizer Build part-64: CLOCK DIVIDER by BMC
author: Eddy Bergman
url: https://www.eddybergman.com/2025/01/Clock-Divider.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>An easy to build clock divider or binary counter with 5 outputs. A simple project and one that was missing from my collection of projects so here it is. For Eurorack or Kosmo.</p><div style="text-align: left;">This is a design from Barton Musical Circuits. With all the projects I have built so far I never built a Clock Divider. So I thought it was time to build one. This is a very easy to build design and I had it up and running within 2 hours not counting designing the layout.</div><div style="text-align: left;">I kept the layout quite thin and long so it can fit behind a small faceplate like a 4hp Eurorack panel.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Below is the schematic for this design, pretty straight forward. You have a TL072 dual opamp comparator with a fixed 110 mVolt signal on the inverting inputs and the clock comes in on the non inverting input. Any signal on the non inverting input higher than +110 mV will flip the comparator to high creating a pulse of +12V on pin 1, the output. That is then brought down to +5V by the voltage divider made up of the 120K and 100K resistors. That's why, <span style="color: #fff2cc;">if you want to run this project on +/-15V you need to change the 120K resistors to 150K resistors</span> to keep that voltage the same.</div><div style="text-align: left;">The CD4024 binary counter/divider chip is then fed with that pulse on pin 1. It divides the input and presents it on the 5 outputs with every negative going pulse slope. The same happens with the second opamp when it is fed a Reset pulse. As long as the Reset input is high the divider will stop working. It will only start running again when the reset input goes low.</div><div style="text-align: left;">Because the input signal goes through an opamp comparator it doesn't matter what type of signal you use on the input. The comparator will change it in to a useable pulse wave.</div><div style="text-align: left;"><span style="color: #fff2cc;"><span>You can actually clock this module with an audio rate signal, like any wave from a VCO and so use the divider as a sort of sub oscillato</span><span>r. (It will output a pulse wave). Each output will be an octave below the previous one.</span></span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: #fcff01;">Make sure you get your CD4024 from a reputable source. I couldn't get this circuit running at first but it turned out my CD4024 was a cheap fake from AliExpress or some such website. So be warned!</span></div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghRu69PWvMNjNEP8a61a1lGKraf6vqeuN6RolHbcLNE51QBGLvkHou5gYcTQ9dAIKA6eZGX1jnGG3TiYWnr3XOJx_ctIwqLtk2Cbga3PPODtchS2ww4G4-2SrrEjtv3Qw7KutxofP5-oM14R6UCIULwRyBiJzD-w2XNf7OYyKkv2Br4eg5IkhV_9eVJ_MJ/s1544/Binary%20Counter%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="715" data-original-width="1544" height="148" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghRu69PWvMNjNEP8a61a1lGKraf6vqeuN6RolHbcLNE51QBGLvkHou5gYcTQ9dAIKA6eZGX1jnGG3TiYWnr3XOJx_ctIwqLtk2Cbga3PPODtchS2ww4G4-2SrrEjtv3Qw7KutxofP5-oM14R6UCIULwRyBiJzD-w2XNf7OYyKkv2Br4eg5IkhV_9eVJ_MJ/s320/Binary%20Counter%20schematic.JPG" width="320" /></a></div><div><br /></div><div>Here is a link to a <a href="https://tinyurl.com/26fn7xn2" target="_blank">FALSTAD SIMMULATION</a> of this circuit.</div><br /><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Here are the layouts I made for this circuit. As always the are verified:</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Wiring diagram:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiC6T8qmGhHiM3eZcaUrF6KLiPIyc7YzTT2PCyNdfESdkuFYl2HzlSRdLjcRCxVbZzOH_W-A2yc7o-XM6EvCaLi9YsysDXePDdyvkce-5_uqAxc6Hf2W2_MUEWVGW6tYg7veXcQGrq6ikWb9otT1zGrwJ09Gp91gJWZ_Y8KAvp-kDm2h-F1t-Wo_G8xbQCy/s7646/Clock%20Divider%20v2a%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3083" data-original-width="7646" height="129" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiC6T8qmGhHiM3eZcaUrF6KLiPIyc7YzTT2PCyNdfESdkuFYl2HzlSRdLjcRCxVbZzOH_W-A2yc7o-XM6EvCaLi9YsysDXePDdyvkce-5_uqAxc6Hf2W2_MUEWVGW6tYg7veXcQGrq6ikWb9otT1zGrwJ09Gp91gJWZ_Y8KAvp-kDm2h-F1t-Wo_G8xbQCy/s320/Clock%20Divider%20v2a%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">You can add up to two more steps to the clock divider because the CD4024 has 7 output pins. So you can add a /64 step (to pin 4) and a /128 step (to pin 3) if you wish. To do this all you have to do is run wires from those pins to two more sockets an LEDs making sure to solder in the 1K resistors. You can connect those resistors straight to the sockets and the LEDs. Make sure each connection has it's own 1K resistor otherwise you're going to pull down the voltage. For instance if you tap the LED off straight from the socket you're going to pull the output voltage down considerably. Look at how it's done on the layout and copy that.</div><div class="separator" style="clear: both; text-align: left;"><br /></div>Stripboard only:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggNkEyTlAgn4D7Ov3Or6ZyfmuE6I6Lzs2yTkabRikJMXAgc9ITHYZB0VYwKHtLOmkRwMwlIZATWOWAo4Sta2rMRtsPRz-kusXc_E7LRTbQ8wUYNu4MclnAsMUKiqaVQJoQXJ8ETEB3ZNujXBWKlkNgI6NzdM1a6eLnXHKPreWFPBxRL9juM8LsX2VDtWyQ/s4534/Clock%20Divider%20v2a%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2310" data-original-width="4534" height="163" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggNkEyTlAgn4D7Ov3Or6ZyfmuE6I6Lzs2yTkabRikJMXAgc9ITHYZB0VYwKHtLOmkRwMwlIZATWOWAo4Sta2rMRtsPRz-kusXc_E7LRTbQ8wUYNu4MclnAsMUKiqaVQJoQXJ8ETEB3ZNujXBWKlkNgI6NzdM1a6eLnXHKPreWFPBxRL9juM8LsX2VDtWyQ/s320/Clock%20Divider%20v2a%20-%20Stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>The voltage regulator is there to feed the CD4024 with power. The CD4024 can be fed with anything from +3V to +15V and the voltage it is fed with also determines the voltage of the pulses it outputs. In my case I wanted my pulses to be a bit higher in voltage than +5V so I put in a 7808 voltage regulator that outputs +8V.&nbsp; You can also leave it out and feed the CD4024 with +12V but then your output pulses will also be +12V.</div><div>You don't have to include that ground strip at the bottom right. You can connect the ground lugs of all the sockets together with one long copperwire and then connect that to a ground point on the stripboard with one wire. That way you can keep the bottom strips free for mounting the board behind a faceplate, like I did (see further down).</div><div><br /></div>Cuts and wirebridges seen from component side.&nbsp;</div><div>Mark the cuts with a Sharpie or Edding marker and then stick a pin through the marked holes and mark them again on the copper side. Now cut the copper strips at the marked positions with a sharp hand held 6- or 7mm drill bit.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEja572nFR_aObOtmSQe1G6W1H_OHQyOjLzJjzbDLlhY8sMdzBisAERlSaP7XCyPkPqRMoXoxNesqibcdhgTpECnZI4evtPqKAio7lzVFOByNE8frZZrEOIRADX8YPPswwWcB1qBdKS6yyGZ0HcssTkRBtOTTi8hhTZLqQhdKbsXYn32XkmqfR2fSCUDGI5s/s4288/03%20Clock%20Divider%20v2%20cuts%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2111" data-original-width="4288" height="158" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEja572nFR_aObOtmSQe1G6W1H_OHQyOjLzJjzbDLlhY8sMdzBisAERlSaP7XCyPkPqRMoXoxNesqibcdhgTpECnZI4evtPqKAio7lzVFOByNE8frZZrEOIRADX8YPPswwWcB1qBdKS6yyGZ0HcssTkRBtOTTi8hhTZLqQhdKbsXYn32XkmqfR2fSCUDGI5s/s320/03%20Clock%20Divider%20v2%20cuts%20wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>And finally the Bill of Materials:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix_wkiXpxX7fV1f9seDq2QoxOQANPCWwtVNoore42pgEp1N4S8GQ8ShZUfCpkJMgfurTxKrRfDGniMTe0vvH9WmRFhcS3MMZynXecnnbFC4gdQY4CuTAECgQjIQjt9xrbJqtO0MW80SzFBaEHD4WgHR1hQz4YcBNMYlUoaCMN9s-kdiTpsAZ6AP_LT1zSY/s760/Binary%20Counter-Divider%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="258" data-original-width="760" height="109" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix_wkiXpxX7fV1f9seDq2QoxOQANPCWwtVNoore42pgEp1N4S8GQ8ShZUfCpkJMgfurTxKrRfDGniMTe0vvH9WmRFhcS3MMZynXecnnbFC4gdQY4CuTAECgQjIQjt9xrbJqtO0MW80SzFBaEHD4WgHR1hQz4YcBNMYlUoaCMN9s-kdiTpsAZ6AP_LT1zSY/s320/Binary%20Counter-Divider%20BOM.JPG" width="320" /></a></div><div><br /></div><div><b><span style="color: red;">OSCILLOSCOPE SCREENSHOTS:</span></b></div><div>Here's a look at the signal coming out of the TL072 comparator (pin1). A nice big bi-polar squarewave. (Btw, I'm feeding the input with a triangle wave of +/5Vpp):</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjX1T5wZdq4jGp4rm7z6UzLYZ-0xjPGymqLMtanYPTKEJ8HX3SLqf4CsAP5uuGg86RmJRVTuFKIclsQk-E26yTFQGzTedQ1wf2hEKknlp6-JlBA3veASaS7thH_Is4h30M2-ZALyZNC7TmiUQ_1XiwvDEgiPLZxJmmeFiwEpp2WyYHJhUq09uLVIJPH-Ox7/s800/Output%20Comparator.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjX1T5wZdq4jGp4rm7z6UzLYZ-0xjPGymqLMtanYPTKEJ8HX3SLqf4CsAP5uuGg86RmJRVTuFKIclsQk-E26yTFQGzTedQ1wf2hEKknlp6-JlBA3veASaS7thH_Is4h30M2-ZALyZNC7TmiUQ_1XiwvDEgiPLZxJmmeFiwEpp2WyYHJhUq09uLVIJPH-Ox7/s320/Output%20Comparator.jpg" width="320" /></a></div><br /><div>After this signal has gone through the diode it's been rectified into a positive squarewave:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYWqWxX0neWWfwFKjv2EmRaYLIIuDIIJTiqzlEUVvxLb_Qra-OygzKVUtUBOfNbei8yM-_J8VNlSKvZTt0qAjF088nqg_A09PifZSdDQViJFB0Gf8MMBSfgKunuqDeXjG7onB-V2bU8wt4EG07xwjJq0cAirSExBNV34s9vKi7JSuZa6hcB4E39oH2A5gu/s800/Output%20Comparator%20after%20diode.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYWqWxX0neWWfwFKjv2EmRaYLIIuDIIJTiqzlEUVvxLb_Qra-OygzKVUtUBOfNbei8yM-_J8VNlSKvZTt0qAjF088nqg_A09PifZSdDQViJFB0Gf8MMBSfgKunuqDeXjG7onB-V2bU8wt4EG07xwjJq0cAirSExBNV34s9vKi7JSuZa6hcB4E39oH2A5gu/s320/Output%20Comparator%20after%20diode.jpg" width="320" /></a></div><div><br /></div>After this wave has gone through the resistor(s) it goes into the clock input of the CD4024 with a voltage of 0 to +4.8V.<div><br /></div><div>The picture below shows the amplitude of one of the outputs:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQfLIgGtPbdYwEkqoV-d6uTJuC01jIazvzUJL1SNr9MNq0iyX53V-r6uGmXJYXrZfGqAleAfMwPYLwCLUVdBqaas6eI3xf_MDjchtFIMTNCuf2NDtXUx0MoC08lMVS0i_m4E761tCyVO45KjY4ImYGjB6kInX0_kaKiVDXIog-BY-2Vjund95Qg_gmP_pO/s800/Output%20clock%20divider.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQfLIgGtPbdYwEkqoV-d6uTJuC01jIazvzUJL1SNr9MNq0iyX53V-r6uGmXJYXrZfGqAleAfMwPYLwCLUVdBqaas6eI3xf_MDjchtFIMTNCuf2NDtXUx0MoC08lMVS0i_m4E761tCyVO45KjY4ImYGjB6kInX0_kaKiVDXIog-BY-2Vjund95Qg_gmP_pO/s320/Output%20clock%20divider.jpg" width="320" /></a></div><br /><div><div><br /></div><div><b><span style="color: red;">BIGGER VERSION:</span></b></div><div>I made a second layout for a clock divider with more outputs re-using the old layout but I put in a CD4040 chip. The chip is mounted upside down from what we normally see. Pin 1 is situated at the bottom right. This will give you divisions upto 1024 times (12 outputs) but <span style="color: #fff2cc; font-size: large;"><span>the layout is not verified!</span>!</span></div><div><span style="color: #fff2cc;"><br /></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgd0nQjl65P1G60UJY7ZG6CA4t_Afjf3XG0_zcrsO2GJuKkx04wNyn5M9MgHdObPpAYxEVm1yNSceBrElqVEj9QdCywsSFYAxNkiNDBU9MB7TFoZAmqPO5LJtO2h63fmmaTEdtVe_ZYeKuimk72alJjf6zYeyPRzwNCMCUnGiaknmR7ZEI4zBtVQmrhEJxg/s7618/Clock%20Divider%20w%20CD4040%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3306" data-original-width="7618" height="139" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgd0nQjl65P1G60UJY7ZG6CA4t_Afjf3XG0_zcrsO2GJuKkx04wNyn5M9MgHdObPpAYxEVm1yNSceBrElqVEj9QdCywsSFYAxNkiNDBU9MB7TFoZAmqPO5LJtO2h63fmmaTEdtVe_ZYeKuimk72alJjf6zYeyPRzwNCMCUnGiaknmR7ZEI4zBtVQmrhEJxg/s320/Clock%20Divider%20w%20CD4040%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>I had confirmation that the layout does work, but it's not perfect.</div><div>You have to mount the 1K resistors straight to the sockets and LEDs otherwise the stripboard would get too big. I've had feedback that the output voltage is much lower with this design so use a 7808 voltage regulator. The CD4040 needs an inverted clock pulse so you need to put a transistor before the clock input. See schematic below. Make sure you use IC's from a reputable source, not from AliExpress.</div><div><br /></div><div>Below is the schematic of a 12 step clock divider. I tested this setup on a breadboard and it works fine.</div><div>This is a different schematic than the one used for the stripboard layout in the picture above and that caused some confusion so I have now made a stripboard layout for this schematic too.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgU2Gn-AQgfMClL_zuvxfmm2KInbkub72QWxrGSBtougQsdjzhu0iwuE8SikrYo2ZsRvgP2aITnSQaxNasfUNS7XhonAC7N573kEc5aP-b3Um7C_75EwX6CwFMbevAu8LkvvzoV1ku5BJunj6YUaBurApZPn3nReizLLSv7f1GDf1X-LN2EnIXnyaCkGO-k/s1171/12%20step%20clock%20divider%20schematic.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="807" data-original-width="1171" height="221" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgU2Gn-AQgfMClL_zuvxfmm2KInbkub72QWxrGSBtougQsdjzhu0iwuE8SikrYo2ZsRvgP2aITnSQaxNasfUNS7XhonAC7N573kEc5aP-b3Um7C_75EwX6CwFMbevAu8LkvvzoV1ku5BJunj6YUaBurApZPn3nReizLLSv7f1GDf1X-LN2EnIXnyaCkGO-k/s320/12%20step%20clock%20divider%20schematic.jpg" width="320" /></a></div><div><br /></div><div>Here's the layout for the schematic above:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifyeDJq8sm_vFmFoH2vOcJicQPwFl71aXgi3fehZV_Fvx1_EkVm7hfLBn0-s3XEDHL2Jwgfl0K9JcGyBCNWvD2q6p_mzKHQg8dMwgldFdumig-p5_4v0zRJEMSaaaVC1hsRnF62mnnkfgGd28EbHXuKrbaMYOpze6O0v48eLI1xjPiH5tiPu_oGNryPHOi/s5764/Clock%20Divider%20w%20CD4040%2012%20stage%20version.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2708" data-original-width="5764" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifyeDJq8sm_vFmFoH2vOcJicQPwFl71aXgi3fehZV_Fvx1_EkVm7hfLBn0-s3XEDHL2Jwgfl0K9JcGyBCNWvD2q6p_mzKHQg8dMwgldFdumig-p5_4v0zRJEMSaaaVC1hsRnF62mnnkfgGd28EbHXuKrbaMYOpze6O0v48eLI1xjPiH5tiPu_oGNryPHOi/s320/Clock%20Divider%20w%20CD4040%2012%20stage%20version.jpg" width="320" /></a></div><br /><div>The manual switch progresses the clock one step per push. You can leave it out if you wish. I don't see the use of it but it only needs a switch and a diode.&nbsp;</div><div>I have put in one output stage as an example. Repeat those 11 more times for all the other outputs. The diodes in series with the 1K output resistors are BAT43 Schottky diodes. I didn't design this circuit so I don't know why they are Schottky's and I think 1N4148 would work just as well. I'm not sure why they're in there at all come to think of it. I think it's to protect the chip from reverse voltage.</div><div>This layout is NOT verified because I didn't build it using this layout. Only on a breadboard so the circuit does work, I know that. Please let me know if you built this layout, if it works so I can verify it.</div><div>I have had some feedback recently which showed some problems when running this at high speeds (as a sub oscillator). I suggest grounding each output by connecting a 100K resistor from each of the 12 outputs to ground. These outputs shouldn't really be left floating. Connect the resistors after the diode at the output sockets. With thanks to Neil for his feedback on this matter.</div><div><br /></div><div><b><span style="color: red;">PICTURES:</span></b></div><div>Here are some pictures I took during building. The stripboard in the pictures may differ a little from the layouts because I later tidied up the layouts and put the components a bit closer together.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF-R4O7vdpnpkUn9s4belMZFpWGlUK1Old5DxUmBC3XV13rP7kCBxXRHj7Yni9cYg5eyJvqD3GwLzYnIOEoB54-ZRkZLLEF24RjPoVnXAwm68SE7s1G-QgNp6K2cba77UKXo4v6du9tVaqrhd0lyypLZ1J1o5eBieJ2mmJGACRQWbco-nMh-Y04GdUCM69/s4000/Finished%20stripboard.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF-R4O7vdpnpkUn9s4belMZFpWGlUK1Old5DxUmBC3XV13rP7kCBxXRHj7Yni9cYg5eyJvqD3GwLzYnIOEoB54-ZRkZLLEF24RjPoVnXAwm68SE7s1G-QgNp6K2cba77UKXo4v6du9tVaqrhd0lyypLZ1J1o5eBieJ2mmJGACRQWbco-nMh-Y04GdUCM69/s320/Finished%20stripboard.jpg" width="320" /></a></div><div><br /></div><div>(My stripboard has one strip more than is shown on the layouts.)</div><div><br /></div>I tried to keep the stripboard as shallow as possible so it can be mounted vertically behind a Eurorack faceplate with a depth of about 4 to 5 CM. In my personal case I built it for my Kosmo DIY synthesizer so I made a faceplate that is 2 CM wide and 20 CM high. The depth came out at 5 CM. There is room at the bottom to drill some holes to put in L-brackets to mount the stripboard behind a panel. I soldered the stripboard straight to the switch lugs of the sockets I used. Making sure the connections between each lug were broken and nothing made contact with it, not even ground.<div><br /></div><div>I mounted the stripboard behind the faceplate by soldering the stripboard to the switch lugs of the sockets I used. The bottom 2 strips are not connected to anything. Make sure when you do this to break the contacts between the different sockets otherwise you will get in trouble. With this method my module came out at a depth of exactly 5 Centimeters.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbmuV8x2ZYRjqqQigmKHwWDU8xuZAjPNBRqNAv4pr3CdpQMmPNSfS3yNXBLf3q2AMnTsyuGjI9hKAM5w06WMmqVG5ti8sfAV-4KSxUNkVF3vHOFe9UY_VryB6Rs0K6uLYyQTEt0aOCSAG4SpLUemMS-OI3gwY7u00R7T7mMyHFgfLg1tdnhsy3wnWnm3g8/s4000/Soldering%20to%20socket%20lugs.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbmuV8x2ZYRjqqQigmKHwWDU8xuZAjPNBRqNAv4pr3CdpQMmPNSfS3yNXBLf3q2AMnTsyuGjI9hKAM5w06WMmqVG5ti8sfAV-4KSxUNkVF3vHOFe9UY_VryB6Rs0K6uLYyQTEt0aOCSAG4SpLUemMS-OI3gwY7u00R7T7mMyHFgfLg1tdnhsy3wnWnm3g8/s320/Soldering%20to%20socket%20lugs.jpg" width="320" /></a></div><br /><div>(The soldering in this corner looks a bit 'how yer doin' but that's because things were soldered, de-soldered and re-soldered again. Believe me, overall the soldering is very neat. I've been soldering since the early 1980's. I know how to do it ^_____^ )</div><div><br /></div><div>Here's a look at the finished module. I built mine in the Kosmo size because I already have one for my Eurorack setup.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKVvHk7YjaAMISqshdXdeQ3QzTieCx-uI7Utl24mri6CtGzpx2cE4EBEFXqJiWHN5COBRaIzUK_bd2BHzS2iFvkbbF7gaXpWXTkSc7rxB8BDvNa9L4vl5_2MQjaNKjcvn1PhyChjg2urpuW78siCN-T1dmx-UPyA4K5OQnybivZ5-Fyyz7LEJDS59tRul8/s4000/Finished%20module-1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKVvHk7YjaAMISqshdXdeQ3QzTieCx-uI7Utl24mri6CtGzpx2cE4EBEFXqJiWHN5COBRaIzUK_bd2BHzS2iFvkbbF7gaXpWXTkSc7rxB8BDvNa9L4vl5_2MQjaNKjcvn1PhyChjg2urpuW78siCN-T1dmx-UPyA4K5OQnybivZ5-Fyyz7LEJDS59tRul8/s320/Finished%20module-1.jpg" width="320" /></a></div><br /><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-z2dxKl9vQwWo30nZAQpwV0XPmSq9x-PoJHwM-BM0rnLn68fKZCcXKpUyWuwtKrhyphenhyphenLDuRl6tMz9AaW-ZG8jMyEl5waSqdgQ5MKRgRL18tKne02Rxr5Q4rNDXCfKgu-ArLAcNBDghaDTFGE64EuOWg-Z9cesRwDWJDWAfwIiVpgS9LXSFlic4eYn24nkXS/s4000/Finished%20module-2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-z2dxKl9vQwWo30nZAQpwV0XPmSq9x-PoJHwM-BM0rnLn68fKZCcXKpUyWuwtKrhyphenhyphenLDuRl6tMz9AaW-ZG8jMyEl5waSqdgQ5MKRgRL18tKne02Rxr5Q4rNDXCfKgu-ArLAcNBDghaDTFGE64EuOWg-Z9cesRwDWJDWAfwIiVpgS9LXSFlic4eYn24nkXS/s320/Finished%20module-2.jpg" width="320" /></a></div><div><br /></div>I used a big voltage regulator because that's what I had in stock but you can use the smaller 78L05 or 78L08 versions in a TO92 package, like a transistor.</div><div>As you can see I bent the regulator over so it won't stick out at the side.<br /><div><br /><div><b><span style="color: red;">VIDEO DEMO:</span></b></div><div>Here's a little video I did while testing the module.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dzaSBomTUtNSA7jv8peI0IsQFaRmle3LVUk8sY5UsWqOyTz-01XU6Ba31U7LcUMo1M0fz6_O97C6E5Qr8oiuA' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div>Okay, that's it for this one. A small project but one that was lacking from my website until now. This is a module that every synthesizer needs especially for drum related patches. If you have any questions or remarks please put them in the comments below or post on the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">special facebook group</a> for this website.</div><div><br /></div><div><br /></div><div><div style="text-align: left;"><br /></div></div></div></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-793030081830606976
title: Synthesizer Build part-65: YAMAHA CS FILTER w IG00156
author: Eddy Bergman
url: https://www.eddybergman.com/2025/02/Yamaha%20CS%20VCF.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>&nbsp;A LP, BP and HP filter in one chip. Not a filter you can just decide to build on a whim though. It uses Yamaha's own IG00156 VCF chip which is very rare and very expensive if you can find one. Like three figures expensive. This projects deals with a Eurorack version of this filter but of course it will work equally well for Kosmo sized synths.</p><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA4bkNCIcPN4rtjhD1wYvWCrEbZ8vthcCH_ccnqck6fBShsEDphs4OFmwYu16svlTwBgA_sGNc8LmZatgVxaJ3U8KbVvv3-eQVPUa0W-WoCk-8ejyymHrNRF80ud_LJ_ZzJ9pyPlRpXhA09S06qSsuzd3nChYTgd81ocweBLqrTNOLnWjlPCtzTam9lWA8/s346/IG00156%20chip.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="321" data-original-width="346" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA4bkNCIcPN4rtjhD1wYvWCrEbZ8vthcCH_ccnqck6fBShsEDphs4OFmwYu16svlTwBgA_sGNc8LmZatgVxaJ3U8KbVvv3-eQVPUa0W-WoCk-8ejyymHrNRF80ud_LJ_ZzJ9pyPlRpXhA09S06qSsuzd3nChYTgd81ocweBLqrTNOLnWjlPCtzTam9lWA8/s320/IG00156%20chip.JPG" width="320" /></a></div><br /><div style="text-align: left;">A good friend of this website, a fellow Dutchman who happens to be an amazing psy-trance producer by the name of Jake Jakaan, signed to a top record label, who uses modules from this website gave me one of these chips. He managed to get hold of a few of them. He states this filter is great for filtering FM sounds from the TH VCO555. It's very low-mid heavy.</div><div style="text-align: left;">It was not easy to find a good schematic for this filter. In fact, all I had was the service manual for the CS-5 and a stripboard layout that someone put together which looked very dodgy and had some mistakes in it (although it did seem to work for my friend but I didn't use it).</div><div style="text-align: left;">I made a completely new schematic for this filter using the original circuit from the service manual and from that I made a new layout, small enough to fit a Eurorack system. The layout turned out to work faultlessly straightaway for which I was very grateful because the IG00156 is not a chip I'd like to blow up. The chip is actually quite robust, I found.</div><div style="text-align: left;">There are two things that are unique to this filter; it has a frequency dependent Q (resonance peak) and a gentle single pole lowpass effect. Resonance (Q) is achieved by damping rather than using a positive feedback loop and because damping will not go to zero the filter can not self oscillate.</div><div style="text-align: left;">This filter is used in all of the Yamaha CS range of synthesizers. Even in their flagship synthesizer, the CS-80. It's a two pole 12dB/Oct. state variable filter. In the CS-80 one chip is used for a lowpass filter and a second one for a highpass filter and in other CS synths like the CS-5, one chip is used for lowpass, bandpass and highpass. The filter I present here has all three functions under a switch although you could have each output go to its own socket but then you have to redesign the output stage or simply bypass the output opamp which I wouldn't advise. You should have opamps with a little bit of gain on the outputs.</div><div style="text-align: left;">Here is the schematic I made and on which I based the layouts below:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMwy_Gf0XY_Jeg_sJHh8gettgyGX9SwX6hFV9dq9YKue8uuQS0D__y47tvv7wxDKTMEy05MjMewJD4Fy1mtcJ1jmKAW3ImizcOabrHsFwGoYmUiGd0dCa68cFYmGELrVJIJjhJGfcg0pr3ICNguTRLc78gImcjq47yiKjTZnsgVwSZgnRNsOCC8HAg_vYr/s4978/00%20Yamaha%20CS-5%20filter%20new%20schematics%20v2c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2855" data-original-width="4978" height="184" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMwy_Gf0XY_Jeg_sJHh8gettgyGX9SwX6hFV9dq9YKue8uuQS0D__y47tvv7wxDKTMEy05MjMewJD4Fy1mtcJ1jmKAW3ImizcOabrHsFwGoYmUiGd0dCa68cFYmGELrVJIJjhJGfcg0pr3ICNguTRLc78gImcjq47yiKjTZnsgVwSZgnRNsOCC8HAg_vYr/s320/00%20Yamaha%20CS-5%20filter%20new%20schematics%20v2c.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Here's a block diagram of the inside of the IG00156 chip:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBYngsppwXph1JGfS-W165nihddleJcOimlCTQpItlGUxGzspD9tbrE-uv2hQlfAZ1VxSfqqOnl81HlWSfhRKynZ48epW6bcQYrfsquJm1o8b5p6jRwG26bhMCmGPado07Bjfqz8CNx-FqlsQQlh1Jnpbe3dTn3TjSwdcJSDAyPMMgsCR7tLRrYXCswSfS/s1227/IG00156%20Pinout%20Discription.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="861" data-original-width="1227" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBYngsppwXph1JGfS-W165nihddleJcOimlCTQpItlGUxGzspD9tbrE-uv2hQlfAZ1VxSfqqOnl81HlWSfhRKynZ48epW6bcQYrfsquJm1o8b5p6jRwG26bhMCmGPado07Bjfqz8CNx-FqlsQQlh1Jnpbe3dTn3TjSwdcJSDAyPMMgsCR7tLRrYXCswSfS/s320/IG00156%20Pinout%20Discription.JPG" width="320" /></a></div><span style="font-size: x-small;">Source: Yamaha IC Guidebook.</span><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">There's an in depth analysis of this filter on the Modwiggler forum: <a href="https://modwiggler.com/forum/viewtopic.php?t=216820" target="_blank">CLICK HERE to read that.</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">I added an audio level control on the input because this filter is rather sensitive to high volume levels. I also added a gain potmeter on the output that gives you the option to set the gain from 2 to 4 times with a 100K potmeter. That is more than enough, but if you want more gain, put in a 500K potmeter which will give you 12 times gain, or 1M which will provide 23 times gain. It will just clip. There's no use in doing that. I really wouldn't advise it.</div><div style="text-align: left;">The schematic says to use +/-15V but I tested it on a dual 12V powersupply and it works fine. The chip inputs for the cutoff and resonance functions are very sensitive and the complete cutoff range is controlled by a voltage that goes from 0 to 0,25V. Only 250 milliVolt for the full range. This is achieved by the voltage divider consisting of the 22K resistor in the cutoff line and the 470 Ω resistor between pins 7 and 8 (or pin 7 and ground really). The potmeters for Cut-off and Resonance need to be fed with +10 volts so I added 1K8 resistors to the pins where the power comes in to cut off roughly 2 volts. You can actually use other values for these potmeters because they're only used as voltage dividers but then you will have to re-calculate the values of those two resistors to make sure the pots receive +10 volts. For instance, if you use 100K potmeters you're need to use two 18K resistors.</div><div style="text-align: left;">I used this schematic to make my stripboard layout which wasn't that difficult because it's quite a simple filter. There aren't many components in it. It worked straight away although at first I couldn't get it working because I had not wired everything up yet. I thought I had connected all the knobs I needed for testing but I forgot the V/Oct input. That needs to be connected to ground if it is not in use and once I had done that the filter sprang to life. After testing I added a V/Oct section to the stripboard layout as explained in the next paragraph.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">VOLT per OCTAVE INPUT:</span></b></div><div style="text-align: left;">At first I had the V/Oct socket grounded through the socket switch but then I realized that isn't needed because the V/Oct input is always connected to ground via the 470Ω resistor.&nbsp;</div><div style="text-align: left;">I applied a voltage divider to the V/Oct input consisting of an 18K and a 470Ω resistor, I went with an octave range of 8 octaves, meaning that the input would get 8 Volts at maximum which would need to be reduced to the same range as the Cutoff input because they all enter the same summer inside the chip (see diagram above). 18K with a 470Ω would give 0 to 203milliVolt which works out perfectly.</div><div style="text-align: left;">Because the filter can not self-oscillate anyway, the filter can not be used as a sinewave oscillator with the resonance fully open. So accurate volt per octave tracking is not an issue and therefore none of these calculations need to be super accurate, it just needs to work so that it sounds good and the filter now tracks nicely up with the octaves.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Here are the layouts I made for this filter. As always they are verified, I used them for my build. As you can see it's a really simple project. There's only 25 resistors, a few capacitors and wirebridges and the chip sockets to put in. The biggest job will be the wiring up of the potmeters and sockets and the making of the panel.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: red;">Wiring diagram</span>. Note that the Resonance potmeter is connected the other way around from all the other potmeters, with ground at the clockwise lug. This is usually the case in VCF's.&nbsp;&nbsp;</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkzgcBxu1S2ibG4yb6V0L1xSdUjVjBu6qTbzyPnQ_c71YZDlNL9YG56yxxXKQTvcF_wk__-xZU73HnO8Fzef1Xqk_AsMGQIbmg8er3qX0noS2QcTD0O80xzpH5x4mWNsI7a1Gt-LRAB_BF3AXPY2UtoQeLK2ibo8cqYHQuV21QFTOgxl67XODVv8jUH9QU/s8535/01%20Yamaha%20CS%20filter%20v5%20-%20Wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4385" data-original-width="8535" height="164" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkzgcBxu1S2ibG4yb6V0L1xSdUjVjBu6qTbzyPnQ_c71YZDlNL9YG56yxxXKQTvcF_wk__-xZU73HnO8Fzef1Xqk_AsMGQIbmg8er3qX0noS2QcTD0O80xzpH5x4mWNsI7a1Gt-LRAB_BF3AXPY2UtoQeLK2ibo8cqYHQuV21QFTOgxl67XODVv8jUH9QU/s320/01%20Yamaha%20CS%20filter%20v5%20-%20Wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><span style="color: red;">Stripboard only:</span></div><div style="text-align: left;">It's best to use bi-polar or none polarized capacitors for the 1µF caps in the filter outputs and on the audio input. This is because we're dealing with bi-polar signals that go through the zero Volt line. The caps don't need to be this specific value. You can use anything between 1 and 10µF without problems.</div><div style="text-align: left;">As you can see all three filter outputs have a 100K resistor to ground. Together with the 1µF capacitor this forms a highpass filter with a cutoff frequency of 1.6Hz so in effect it keeps DC voltage from passing and all the other frequencies get through. Make sure you use high quality capacitors for the two 1,5nF filter caps. I used Polystyrene ones which always sound the best.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwR_XMfcX1CQF8_AixdlbfrbsGxT_nS3bTXd2GKT5hRJT5mq9puDJwo9XJQhyaqZWhCdjiuaQ1Gl7uMD5FayzzkRG-MxNLtPNfch4amGkoZ4J_YkJMCkD2SjyiDlA_sqoaxpgoCiWxStz5T2al2cosrmSQv3UHFK2I6lMdo9MVraNhlWHrU0svi13A-TO7/s4500/02%20Yamaha%20CS%20filter%20v2b%20-%20Stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3074" data-original-width="4500" height="219" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwR_XMfcX1CQF8_AixdlbfrbsGxT_nS3bTXd2GKT5hRJT5mq9puDJwo9XJQhyaqZWhCdjiuaQ1Gl7uMD5FayzzkRG-MxNLtPNfch4amGkoZ4J_YkJMCkD2SjyiDlA_sqoaxpgoCiWxStz5T2al2cosrmSQv3UHFK2I6lMdo9MVraNhlWHrU0svi13A-TO7/s320/02%20Yamaha%20CS%20filter%20v2b%20-%20Stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><span style="color: red;">Cuts and wirebridges</span>. As always, mark the cuts with a Sharpie or Edding pen on the component side and then stick a pin through the marked holes and mark them again on the copper side. Then cut the strips at the marked positions with a sharp hand held 6- or 7mm dril bit. Make sure you work accurately!!</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWX6Qouo7HauikV7ka2w__4td23QmGyOJr_z1CuMYTa-0tnR8V89iCIAASIYLEFDMrjJzkCMOJjdb7OVVqp2EXoFuryDBqETRThz9UQbkZ9G5AOCnOSm7AXD09mG3g7JQYmPmJsQOg3Pp4EUW02khPjYnkd_AGRawM_V5_YYlUODXNse9M7CFa8EbLZjYt/s3983/03%20Yamaha%20CS%20filter%20v2b%20-%20Cuts%20and%20Wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2913" data-original-width="3983" height="234" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWX6Qouo7HauikV7ka2w__4td23QmGyOJr_z1CuMYTa-0tnR8V89iCIAASIYLEFDMrjJzkCMOJjdb7OVVqp2EXoFuryDBqETRThz9UQbkZ9G5AOCnOSm7AXD09mG3g7JQYmPmJsQOg3Pp4EUW02khPjYnkd_AGRawM_V5_YYlUODXNse9M7CFa8EbLZjYt/s320/03%20Yamaha%20CS%20filter%20v2b%20-%20Cuts%20and%20Wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">And here is the bill of materials. It won't be easy to find an IG00156 chip. They are long out of production so your best bet is websites that sell rare synthesizer components. They go on Reverb for $189,- but that is top dollar. They should go for between $70,- a $100,-&nbsp;</div><div style="text-align: left;">I did not include any bypass caps or extra electrolytic caps for the voltage rails. If you want to include those you need to add them to the list (2 x 100nF and 2 x 10µF/25V). They're not on the layout or schematic either but there's room enough on the stripboard to put them in over the voltage rails.</div><div style="text-align: left;">The two trimpotmeters should really be the normal kind and not multiturn trimmer. There's really no use in having multiturn trimmers because there's no need for that kind of accuracy.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglRgha-ZGYbj3M0q0auNX6ZpyKlOTkv4MhfzVMzTZgzw3a7wvVEE8mC6b_o70eQmM_nklKLVS9fWqF9gkreQPsEWmwqGkztBgyJMUGztVEJXaYoajuqe6Vj2x5Q0YNVmT4bShCvJKt5__88CGXroPs1lRY2wBgWQViIySaKFZfDccaQaxDXQ9vv7jokU91/s892/04%20Yamaha%20CS%20filter%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="514" data-original-width="892" height="184" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglRgha-ZGYbj3M0q0auNX6ZpyKlOTkv4MhfzVMzTZgzw3a7wvVEE8mC6b_o70eQmM_nklKLVS9fWqF9gkreQPsEWmwqGkztBgyJMUGztVEJXaYoajuqe6Vj2x5Q0YNVmT4bShCvJKt5__88CGXroPs1lRY2wBgWQViIySaKFZfDccaQaxDXQ9vv7jokU91/s320/04%20Yamaha%20CS%20filter%20BOM.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>NOTE: There is a Hongkong based listing of the IG00156 chip floating around on the internet selling them for €10,- Don't fall for that, it's a scam!!</div><br /><div style="text-align: left;"><b><span style="color: red;">PICTURES:</span></b></div><div style="text-align: left;">Here are some pictures from the build proces:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7FuSO_ZiGK8NtVJmNuJTYFkZeY0DW8oRVb_CW9Fa-fYH4YkWyviVmuAGyi2bceHtrHdU_Pn5APeFUJ4CqrUyqPQcRFB4rdgqsr2Vb5QV8vgxVo3PE8GfNK9QjHeYfpkO4lYtJL0tZv8Hk5t0bJlE7AbEkCaapoScigwAi0zBGFqFOBO9vJvKWl_ry9EP1/s2860/01%20Cuts%20and%20wirebridges%20done.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1916" data-original-width="2860" height="214" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7FuSO_ZiGK8NtVJmNuJTYFkZeY0DW8oRVb_CW9Fa-fYH4YkWyviVmuAGyi2bceHtrHdU_Pn5APeFUJ4CqrUyqPQcRFB4rdgqsr2Vb5QV8vgxVo3PE8GfNK9QjHeYfpkO4lYtJL0tZv8Hk5t0bJlE7AbEkCaapoScigwAi0zBGFqFOBO9vJvKWl_ry9EP1/s320/01%20Cuts%20and%20wirebridges%20done.jpg" width="320" /></a></div><div><br /></div>All components soldered on:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4dVoBDvFFyLlocnkfM8tRle6gcOmfXXpoJ0bHPrJsaxCVdD3r3TDUQgf7r5ArdDF4ntjPv0OiqNUosGZ_eDJb-y_8r9yEsaxk8A7ldDm-qK0e3FQIRXj6jSCQIZIid6mHYf25oG3uA_klrKiFg-A1t_BgQ-W4mOhbDvvR1n8jGW0J4VSpLfIXuOSsZxPi/s3640/02%20Yamaha%20CS5%20board%20ready.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="3640" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4dVoBDvFFyLlocnkfM8tRle6gcOmfXXpoJ0bHPrJsaxCVdD3r3TDUQgf7r5ArdDF4ntjPv0OiqNUosGZ_eDJb-y_8r9yEsaxk8A7ldDm-qK0e3FQIRXj6jSCQIZIid6mHYf25oG3uA_klrKiFg-A1t_BgQ-W4mOhbDvvR1n8jGW0J4VSpLfIXuOSsZxPi/s320/02%20Yamaha%20CS5%20board%20ready.jpg" width="320" /></a></div><div><br /></div>Testing:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrBt_FdP_VD_GOXdNRoNYgmuOpPaPQDSXRfN9UIqQcEHwGoNBfKLICg7XfkNSjW_yWKPYk2CBXg9kSBuQXHlbegOCwPbD6mNtas3oXVkQdaqDgl6wE1Il0bo7N1E3Vl-qJA3lR0cOReBuWiYV-WoX5tknBWvwYTtwfjIirpyIVPwIe7UfeBO-9zNfE89hR/s4000/Board%20being%20tested.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrBt_FdP_VD_GOXdNRoNYgmuOpPaPQDSXRfN9UIqQcEHwGoNBfKLICg7XfkNSjW_yWKPYk2CBXg9kSBuQXHlbegOCwPbD6mNtas3oXVkQdaqDgl6wE1Il0bo7N1E3Vl-qJA3lR0cOReBuWiYV-WoX5tknBWvwYTtwfjIirpyIVPwIe7UfeBO-9zNfE89hR/s320/Board%20being%20tested.jpg" width="320" /></a></div><br /><div>Drilling the panel using a copy of the panel design I made in Photoshop as a dril guide:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigUBrwMgJJ6-e1xYtv3aVJ8SXYyvYGxuXaybyIrkoSkq7mIFOK5MZSpIKqBd61o68EKCyfwJlokTGB7-G2VnLYLavrlS_pjridSW9B3tMDkEQpP7VhWBpDBxmXelYZSJyD0hHL6xiTF2Z9UNZMMDHlfA_wJN5giuvJILt4olQv62Eaqko_tr_D9oMy8F4g/s3521/Panel%20drilling.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="3521" height="205" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigUBrwMgJJ6-e1xYtv3aVJ8SXYyvYGxuXaybyIrkoSkq7mIFOK5MZSpIKqBd61o68EKCyfwJlokTGB7-G2VnLYLavrlS_pjridSW9B3tMDkEQpP7VhWBpDBxmXelYZSJyD0hHL6xiTF2Z9UNZMMDHlfA_wJN5giuvJILt4olQv62Eaqko_tr_D9oMy8F4g/s320/Panel%20drilling.jpg" width="320" /></a></div><br /><div>Waterslide design applied to the faceplate and now drying on the central heating. All the creases you see will be gone by the time this is dry.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkGep4ORTAJUROmDV1aMamHzvXgT395tdVddsTxz7VN0e0vpke7LGOZ8fGCWrXEPBCbO024czhyphenhyphenFGON74IZfES0zU0ikeoXLv1AfdvPx9evkIkzsV7VW2uabSKF6lBu3-FlWjr-Mq6wDMlKvZjS22rcxViTJr_QIQ5gbKPRvH0hvsQ73guC115HuQ058tE/s4000/Waterslide%20drying%20on%20CH.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2252" data-original-width="4000" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkGep4ORTAJUROmDV1aMamHzvXgT395tdVddsTxz7VN0e0vpke7LGOZ8fGCWrXEPBCbO024czhyphenhyphenFGON74IZfES0zU0ikeoXLv1AfdvPx9evkIkzsV7VW2uabSKF6lBu3-FlWjr-Mq6wDMlKvZjS22rcxViTJr_QIQ5gbKPRvH0hvsQ73guC115HuQ058tE/s320/Waterslide%20drying%20on%20CH.jpg" width="320" /></a></div><br /><div>Finished panel ready to receive the pots and sockets etc. After the waterslide design has dried we cut out the holes with a very sharp hobby knife and then apply two more layers of clear acryllic lacquer and let it dry overnight.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiweivdjpV9vCeqgUQd4ahboGB52BmHhryUvuwSekrxVFu55kBHrAHxmuhNBV7yhxxTEzcui0R8FXfnTlVKZX2qLKXHFqxVd6BopSY39VLN82HkG0fOluimI88s_7kz0pjlJ1An5l-L6pk3eECoYgt7SWrjcuivlMgcIISSL45HaYuEQ_doCS0X_z8Or72/s2273/Panel%20finished.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2273" data-original-width="2096" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiweivdjpV9vCeqgUQd4ahboGB52BmHhryUvuwSekrxVFu55kBHrAHxmuhNBV7yhxxTEzcui0R8FXfnTlVKZX2qLKXHFqxVd6BopSY39VLN82HkG0fOluimI88s_7kz0pjlJ1An5l-L6pk3eECoYgt7SWrjcuivlMgcIISSL45HaYuEQ_doCS0X_z8Or72/s320/Panel%20finished.jpg" width="295" /></a></div><div><br /></div><div>Finished module. The module is 14hp wide (7 CM) and 3.7 CM deep.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgca_uSYagpdAB3b24qvmnunb1FDpHfQ3Z9TG8atYnnvxb5hNTNTJJUQ-sAsaosHZ5T-6gHR5QkghJUP8Mx4KN_HsuGJQ6WeuAn0cVKCpwPcIA-ixgzx3ZZMyyvWb9ml661vCtahgjXL6F4TY_iWL-O6_y67eIDyg-RdhHdr7t_bIOLcUu0Mp_hTUfqidBg/s3616/Finished%20module-1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3616" data-original-width="2024" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgca_uSYagpdAB3b24qvmnunb1FDpHfQ3Z9TG8atYnnvxb5hNTNTJJUQ-sAsaosHZ5T-6gHR5QkghJUP8Mx4KN_HsuGJQ6WeuAn0cVKCpwPcIA-ixgzx3ZZMyyvWb9ml661vCtahgjXL6F4TY_iWL-O6_y67eIDyg-RdhHdr7t_bIOLcUu0Mp_hTUfqidBg/s320/Finished%20module-1.jpg" width="179" /></a></div><div><br /></div><div>I only had a 4 way rotary switch, that's why the HP mode on the panel has 2 settings. Lugs 3 and 4 of the switch were connected together.</div>Side view:<div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2GMaR4PiPOyR9pqKHODbkXIgoGttm6YrgWi9a567WbwDk3rbct8QH38PLu3U70eyeqJBmNB4RugLswEEWlOETYmbt7v9-aMUE4kJDE_SqePGPYGuHgg3ZJ3-MdScC6Ym124SzS-SIeFc1VU0iArKWS8iSkXgfWd6Vzs-nI0ukJJHzp4fvwOwEeaAyv946/s3604/Finished%20module%20side%20view-1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3604" data-original-width="2012" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2GMaR4PiPOyR9pqKHODbkXIgoGttm6YrgWi9a567WbwDk3rbct8QH38PLu3U70eyeqJBmNB4RugLswEEWlOETYmbt7v9-aMUE4kJDE_SqePGPYGuHgg3ZJ3-MdScC6Ym124SzS-SIeFc1VU0iArKWS8iSkXgfWd6Vzs-nI0ukJJHzp4fvwOwEeaAyv946/s320/Finished%20module%20side%20view-1.jpg" width="179" /></a></div><br /><div class="separator" style="clear: both; text-align: left;">Side and back view:</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyduTu_h6XXA7R7mx4Cd7ifDGD4Y7jl_07ds5X8OCKx2xn44hIzut3ULsmJ-g83xFtI7TMpZqQLuAHtBQftLKPVDbF8vVMaVINL6uqRwQzqPqHFBQCsRNbgx79FPdmF5G2U0Av48dWxqVZd6qLfpZ_9HMfn23vaYnMo-jEckPnfI5fwU0c9mcoMCI1Z0Fq/s3316/Finished%20module%20side%20and%20back%20view.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3316" data-original-width="1844" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyduTu_h6XXA7R7mx4Cd7ifDGD4Y7jl_07ds5X8OCKx2xn44hIzut3ULsmJ-g83xFtI7TMpZqQLuAHtBQftLKPVDbF8vVMaVINL6uqRwQzqPqHFBQCsRNbgx79FPdmF5G2U0Av48dWxqVZd6qLfpZ_9HMfn23vaYnMo-jEckPnfI5fwU0c9mcoMCI1Z0Fq/s320/Finished%20module%20side%20and%20back%20view.jpg" width="178" /></a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Here's an oscilloscope screenshot of a squarewave wave in LP mode with full resonance applied:</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVquPQr11oF9cRdYHHaZa7pAeeQidfeY2Ndr8KicEfpTFZVlUX3-yI4_hlS-R8VLoHglii_a1NhtjTkEyG4SdZRc-JkA-EQ-GL1_oErAYUieohwLn1Qn-NZh0L2aDwkmFIRUC62LUlnbtUq1NI1ufS28x6VZthcHkiCupn0ZiiZ2Hic9GX67s7XDnKV0ML/s800/Yamaha%20VCF%20Full%20resonance.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVquPQr11oF9cRdYHHaZa7pAeeQidfeY2Ndr8KicEfpTFZVlUX3-yI4_hlS-R8VLoHglii_a1NhtjTkEyG4SdZRc-JkA-EQ-GL1_oErAYUieohwLn1Qn-NZh0L2aDwkmFIRUC62LUlnbtUq1NI1ufS28x6VZthcHkiCupn0ZiiZ2Hic9GX67s7XDnKV0ML/s320/Yamaha%20VCF%20Full%20resonance.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: left;"><br /></div><div><b><span style="color: red;">CALIBRATING THE FILTER:</span></b></div><div>There are two trimpots on this filter that need to be set.</div><div>The first one is the 100K trimpot. You use this to set the throw of the Cut-Off potmeter. Set it in such a way that you get the most resolution of the Cut-Off potmeter.</div><div>The other one, the 200K, is used to set the Resonance to maximum. Turn up resonance and turn the trimmer until you're at max resonance. This will probably be around the middle of the trimmer at about a 100K.</div><div>It's best to have normal trimpots not multiturn ones. There's no need for those and the normal trimpots are easier to use.</div><div><br /></div><div><b><span style="color: red;">VIDEO DEMO:</span></b></div><div>Here's the first test I did after finishing the project. This filter literally makes the room shake. If you turn up the volume (with good speakers or headphones) you will hear stuff starting to rattle in the background. It's a very bass heavy filter which really sounds great!</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dzPIDxwHlqNvrJsm_M8fLBOGIpL6cld94_N8uTfYAmObPWsZ0K5uE9jO0zB5GP70DPRWEaviKCepgS_m0irOQ' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div><div class="separator" style="clear: both; text-align: left;">Here's a short demo I made with the X4046 VCO hard synced by the 555 VCO going through the filter.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/QuVs1-y7QxM" width="320" youtube-src-id="QuVs1-y7QxM"></iframe></div><br /><div class="separator" style="clear: both; text-align: left;">Here's an other video I found on YouTube dealing with the CS-5 Lowpass filter:</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><a href="https://www.youtube.com/watch?v=5F8_RfVzO2A" target="_blank">https://www.youtube.com/watch?v=5F8_RfVzO2A</a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Here's a Facebook video of my friend Jake Jakaan using 3 of these filters in bandpass mode to create a formant filter that makes sounds akin to human speech.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><a href="https://www.facebook.com/share/v/1A2Q6Ws1AE/" target="_blank">https://www.facebook.com/share/v/1A2Q6Ws1AE/</a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Okay that's it for this article. Not a filter anyone can build alas but this website is an archive of all the modules I built myself so it certainly belongs here. I also noticed that Yamaha filter schematics that specifically deal with the CS filter are almost non existent on the internet except for the service manuals. So I hope this article will provide at least one good schematic for those looking for it.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">If you have any questions or remarks about this project then please put them in the comments below or post them on the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">special Facebook group</a> for this website.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><br /></div><br /><div style="text-align: left;"><br /></div></div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-2176996434143384829
title: Synthesizer Build part-66: ROLAND TB-303 VCF.
author: Eddy Bergman
url: https://www.eddybergman.com/2025/03/TB303-VCF.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<p>The famous acid house filter from the Roland TB-303. A Eurorack friendly project and a ladder-filter that sounds amazing.&nbsp;</p><div style="text-align: left;">[EDIT Jan.2026] I have revised the schematic and layouts after a long midnight chat session with my friend Jake Jakaan who uses these filters in his psy-trance music. He made some changes to this filter that make it work much better for that Acid house sound. He built 3 of these so far according to the schematic below. There are PCBs available for this new version. See&nbsp;<a href="https://www.eddybergman.com/p/pcb-service.html" target="_blank">'PCB Service'</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">TO ACID OR NOT TO ACID.</span></b></div><div style="text-align: left;">This is the 14th filter on this website and this is one with a very specific sound so I thought let's make a project out of this because I think that this filter in particular will be of great interest to many people because of it's unique sound. I based my layout on a layout that Jake Jakaan made from a schematic he found online in combination with the original service manual schematic of the TB-303 (TB 303 stands for Transistor Base 303).&nbsp;</div><div style="text-align: left;">I have to warn you, the filter sounds great in itself but to get that Acid-House sound out of it requires more than just this filter. That specific sound is a delicate balance between filter settings and envelope input, slide of glide between the sequenced notes and maybe some LFO or offset voltage added. Playing legato might help (where not every note produces a gate signal), experiment with that.</div><div style="text-align: left;">When I first tried this filter I didn't get anything near that classic sound. However, I found some tips and instructions online which helped a lot.&nbsp;</div><div style="text-align: left;">Resonance needs to be open to self oscillation. The cutoff control is most effective in the first part of the potmeter throw.</div><div style="text-align: left;">I posted a very helpful short video at the bottom of this article below the video demo's that tels you how to get that sound.</div><div style="text-align: left;">I got close in the end though as you can see in the demo video below.&nbsp;</div><div style="text-align: left;">This is really the first filter I ever built that you have to learn how to use. I'm getting there tho ;)</div><div style="text-align: left;">The demo video is still from the earlier version. This new updated version works much better and is absolutely capable of delivering that acid squeel sound..</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">A LITTLE HISTORY:</span></b></div><div style="text-align: left;">The TB303 was a bass synthesizer made by Roland and released in 1981. It was supposed to simulate bass guitars but it sounded nothing like a bass guitar and it became a commercial flop. It was taken out of production in 1984 after a run of 10.000 units. These were sold off cheaply by Roland. (If only we knew then what we know now @___@)&nbsp; However, cheap second hand 303's were picked up by electronic musicians and the twirping, squelching sound became a main stay of electronic dance music genres like Acid House, Chicago house and Techno. There are now numerous clones on the market and original units fetch prices of over $3000,- on the second hand market. Originals were also modified in the 80's, adding distortion and external inputs (Nova mod).</div><div style="text-align: left;">The TB-303 was designed by Tadao Kikumoto who also designed the TR-909 drum machine. It has a single oscillator which produces a sawtooth wave or a squarewave. This goes into a 24dB/Oct lowpass ladderfilter which is manipulated by an envelope generator.&nbsp;</div><div style="text-align: left;">I have read that it's actually an 18dB/Oct lowpass filter instead of 24dB but I don't know if that's true.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC:</span></b></div><div style="text-align: left;">Here is the revised schematic version 3. It's a bit low resolution because this was originally a file with a black background and bright green lines. I took it into Photoshop and inverted the image and brightened it up and made it more legible. I also included the transistor pinouts. All transistors on the schematic are NPN 2SC945's except for the two at the bottom marked 733. Those are two 2SA733 PNP transistors.</div><div style="text-align: left;">The transistors in the ladder are not numbered to avoid this schematic becoming a mess of numbers but the other transistors are numbered the same as on the layouts.</div><div style="text-align: left;">In the schematic below two resistors have been changed for trimmers, the 10K and the 100K to the wiper of the Cutoff potmeter. The 3rd pins on these trimmers are not connected. Why is that you might ask. Well electrically it makes no difference but leaving pin 3 unconnected can give you less noise in analog circuits. It's easier to de-solder should that be necessary and in case of a failure the result will be an open circuit instead of maxed out resistance. Easier to find that in a circuit.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG0-XjXa31qya4fM_zS3_dEd19Y_9gOc9JLT13sfTMFD7LdjJqsLIbX-ktGfikodZCnfwFbjTz-bRgBoChazWFrdLHNEj-eRsRTIv2NNGZ1a03iX11BTmWk7qGYEpoStvO4hxAKZJcGSlRzTxqhnxqmCEfJeTIHP-sGPA-raSzyqyR22XpE9cOc5aCRRyQ/s1213/Schema%20303%20VCF%20Revised%20Version.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1213" data-original-width="899" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG0-XjXa31qya4fM_zS3_dEd19Y_9gOc9JLT13sfTMFD7LdjJqsLIbX-ktGfikodZCnfwFbjTz-bRgBoChazWFrdLHNEj-eRsRTIv2NNGZ1a03iX11BTmWk7qGYEpoStvO4hxAKZJcGSlRzTxqhnxqmCEfJeTIHP-sGPA-raSzyqyR22XpE9cOc5aCRRyQ/s320/Schema%20303%20VCF%20Revised%20Version.jpg" width="237" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div>The capacitors in the schematic are not marked as polarized but the 10µF electrolytic caps are obviously polarized and for the 1µF you can use either type. The layouts use un-polarized caps.&nbsp;</div><div>In the layouts below I actually added a second CV input on top of the Envelope input. I connected that the same way as the envelope input, using a 56K resistor to T7. I find two CV inputs on a filter almost a necessity.</div><div><br /></div><div>Here's the filter part of the service manual schematic for reference. It has two 2K2 resistors from +12V to T1 and T2 but that's a misprint. It needs to be 22K:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj86sB9trtPN0jGt0BtJNZeWGJU9d1Jyp7VuLs6IvyBF4gfeSHhH7pso8HReWyD4IMNL9ohsmj7RJA0rxGZnIsuXLeXiWW8YxBQ2SYHgiXMdtWh3_wwNd7QDaWSZteBKoLIR72kIAgE8ZjVg2mxxz9xK3OVNBkRWRLFw6w5yZ4yBZbiNkrXK0jyW81o6MHy/s1634/303%20Service%20manual%20schematic.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="596" data-original-width="1634" height="117" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj86sB9trtPN0jGt0BtJNZeWGJU9d1Jyp7VuLs6IvyBF4gfeSHhH7pso8HReWyD4IMNL9ohsmj7RJA0rxGZnIsuXLeXiWW8YxBQ2SYHgiXMdtWh3_wwNd7QDaWSZteBKoLIR72kIAgE8ZjVg2mxxz9xK3OVNBkRWRLFw6w5yZ4yBZbiNkrXK0jyW81o6MHy/s320/303%20Service%20manual%20schematic.JPG" width="320" /></a></div><div><br /></div><div style="text-align: left;">The filter does not use any negative voltage. It is powered by +12V and it also needs a +5V powerrails which is provided by the onboard voltage regulator. The +12V goes through a 100 Ohm resistor. I wondered whether or not to include that but I wanted to see how much voltage that resistor takes off from the original 12V and it's only 0.2V so I left it in but I lowered it to 10 Ohm..</div><div style="text-align: left;">Staying true to the original includes using 2SC945 transistors for the NPN trannies and 2SA733 for the PNP transistors. You can however use other transistors like the BC547 and BC557 but beware when you do because you'll have to redo the layouts. The 2SC945 and 2SA733 have an unusual pinout. It's emitter to the left, collector in the middle and base to the right. I had to constantly keep this in mind when designing the layouts and it wasn't easy but I managed it in a day.</div><div style="text-align: left;">The transistor pairs at the top and bottom of the ladder and the transistors next to it with the common emitter connection need to be matched pairs!! Very important with this filter.</div><div style="text-align: left;">I came to the conclusion that my usual method of matching on Hfe didn't meet the case here so I did it with setting up a differential amplifier on a small breadboard. The method is shown below.</div><div style="text-align: left;">I ordered a hundred of the 2SC945's and made 10 matched pairs and I used those transistors in this project even with the middle trannies in the ladder. I thought I might aswell use all matched transistors but you don't have to do that. You can use other transistor types like the BC547 and BC557 which are used in the Doepfer A-103 VCF6 filter but you'll have to redesign the layout because their pinout is different from the 2SC and 2SA transistors I used.</div><div style="text-align: left;">Two resistors have been replaced by trim pots, one in the Cutoff wiper to T7 and one at the bottom of the transistor ladder. These trimmers are mounted with pin 3 not connected.</div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">MATCHING TRANSISTORS.</span></b></div><div style="text-align: left;">For this filter I didn't want to rely on just measuring Hfe and matching the transistors on that value. I used the Ian Fritz methode. I took a small piece of stripboard and set up a simple differential amplifier with two transistors. <span style="color: #fcff01;">If the transistors are matched then the voltage measured between the two emitters should be zero</span>. Make sure you let the transistors cool down after handling them with your fingers.</div><div style="text-align: left;">For D1 any silicon diode will do. The voltage drop over this diode ensures both transistors get exactly the same Collector Base voltage. Beware this setup requires a dual voltage source of +/-12V. You also need to make sure the two 100K resistors have as near as possible the same value.</div><div style="text-align: left;"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBU1WQLe5OjHSSn1Ik0-P6TAJx5eUBCrvZ3QkZlSzN2uS6Wz4cPpsVpCdW-uyOYLdCS-aAgdlei00fG0QQXNq1OlX4WzPB3dhWp31EnFMCMgiiL2hCktz6_EhnhXN2Bhxx7HhRwdkqyn4hNL9QFk76TIV0zamgp7bkfmM1tfZNnYtYuu5vU-0jfB3kMswj/s1056/Transistor%20Matching%20Circuits.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="606" data-original-width="1056" height="184" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBU1WQLe5OjHSSn1Ik0-P6TAJx5eUBCrvZ3QkZlSzN2uS6Wz4cPpsVpCdW-uyOYLdCS-aAgdlei00fG0QQXNq1OlX4WzPB3dhWp31EnFMCMgiiL2hCktz6_EhnhXN2Bhxx7HhRwdkqyn4hNL9QFk76TIV0zamgp7bkfmM1tfZNnYtYuu5vU-0jfB3kMswj/s320/Transistor%20Matching%20Circuits.jpg" width="320" /></a></div></div><div style="text-align: left;"><br /></div><div style="text-align: left;">You then need to switch the transistor positions and measure again. I didn't bother with that though. An other method is to leave one transistor in place and change the second one. If you find two transistors that display the same voltage difference from the fixed transistor, those two will be matched.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">This method worked very well. I used matched pairs throughout the ladder filter and also for the differential amplifier made up of T1 and T2.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Please read the full article on transistor matching by <a href="https://web.archive.org/web/20151002134800if_/http://home.comcast.net/~ijfritz/MiscProj/transmat001.pdf" target="_blank">downloading the article by Ian Fritz.</a>&nbsp;</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Below is a picture of my transistor matching stripboard. I can get them matched to within 1/10,000th of a Volt or 0.1 milliVolt. I cut a DIP8 IC socket in half and connected the top and bottom pin together. I use that as socket for the transistors under test and with this setup I can measure NPN transistors with different pinouts because I have an emitter contact at the top and the bottom. I placed the sockets away from eachother to make it easier to change transistors without influencing the other transistor. I usually accept transistors that measure a difference within 0.3 milliVolt or lower. If you go to extremes with accuracy you'll be measuring until doomsday before you find a match.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_1w1nJZCPPAG-XJZZr5QJMpNWjnnxGZanRgzSlEIeOn22okqAvKCsha2jJNnAyzHe6wIsJi46A7vMeoYMKly5D631Xzj5Ivrk-LWdKgbw5nI1jCutba9SXwMyvijD-aS787bF4TfLJ-pqGWK_Xn-lKwBmj_rknJgfhWisfzMd7pneuwFjvk7OADJiHdGl/s3704/My%20trans%20match%20setup.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2736" data-original-width="3704" height="236" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_1w1nJZCPPAG-XJZZr5QJMpNWjnnxGZanRgzSlEIeOn22okqAvKCsha2jJNnAyzHe6wIsJi46A7vMeoYMKly5D631Xzj5Ivrk-LWdKgbw5nI1jCutba9SXwMyvijD-aS787bF4TfLJ-pqGWK_Xn-lKwBmj_rknJgfhWisfzMd7pneuwFjvk7OADJiHdGl/s320/My%20trans%20match%20setup.jpg" width="320" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">LAYOUTS:</span></b></div><div style="text-align: left;">Below are the layouts for this project. I redid all the layouts to match the revised version of the schematic.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: red;"><b>Wiring:</b></span></div><div style="text-align: left;">I numbered the transistors that are not part of the ladder, using the same order as in the schematic so you can easily understand which transistor is which when you compare it with the schematic. The light grey transistors are the 2SA733's. I included an extra CV input with the same level control as the Envelope input.&nbsp;</div><div style="text-align: left;">The transistors in the ladder have the base and collector connected together so they actually function as diodes.</div><div style="text-align: left;">The envelope and CV input level potmeters used to have pin 3 connected to a 10K resistor but I took those resistors out and they are now connected straight to the emitter of T8.</div><div style="text-align: left;">If you look closely at the audio input you can see a 220K resistor on the stripboard that isn't used. I have the audio going straight into the filter through the 1µF cap. Originally that 220K should be in series with that cap but I think the value is too high. I later experimented with a lower value but you can also leave the resistor out.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgONSiV9RjnQUehhy7qYdKZnsbC93-MeQ-Au9xhZq92dxyOMpufRtVBbmQ5ARRk6BPevqPbMbrBAYkBSIyoIOrDEbSaD5XZHkZoZG4BWiEJI_Uzkg9MrlNd3HHVowOA3fkhkNYiyj_gKjLB8rGfqjV4J2G7u3SVc-QfQoR0J6cqDIXLlPyFtbTfczuxPfD_/s10142/303%20VCF%20JJ%20v3%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3997" data-original-width="10142" height="126" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgONSiV9RjnQUehhy7qYdKZnsbC93-MeQ-Au9xhZq92dxyOMpufRtVBbmQ5ARRk6BPevqPbMbrBAYkBSIyoIOrDEbSaD5XZHkZoZG4BWiEJI_Uzkg9MrlNd3HHVowOA3fkhkNYiyj_gKjLB8rGfqjV4J2G7u3SVc-QfQoR0J6cqDIXLlPyFtbTfczuxPfD_/s320/303%20VCF%20JJ%20v3%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><span style="color: red;"><b>Stripboard only</b></span> view:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0-e4UxtYk6DE-fHpBIIkWC9Gci00hUzIh3zccqSfZ9TEkFmlXoUYdx30o1D0W5KQK3tKCPJaV0Q4jv5-MChe9hj037d61dN6LPIpRp50q-g72V7twV7jpxDvxCicVMIh06GZCeRSibTP4uw1-Hnw0fnLvnPjGcFX80FOV1muzFtQwaW80G8KF-2V1jTX4/s7000/303%20VCF%20JJ%20v3%20-%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4150" data-original-width="7000" height="190" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0-e4UxtYk6DE-fHpBIIkWC9Gci00hUzIh3zccqSfZ9TEkFmlXoUYdx30o1D0W5KQK3tKCPJaV0Q4jv5-MChe9hj037d61dN6LPIpRp50q-g72V7twV7jpxDvxCicVMIh06GZCeRSibTP4uw1-Hnw0fnLvnPjGcFX80FOV1muzFtQwaW80G8KF-2V1jTX4/s320/303%20VCF%20JJ%20v3%20-%20stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><span style="color: red;"><b>Cuts and wirebridges</b></span> seen from the component side. As always, mark the cuts on the component side with a Sharpie or Edding marker and then stick a pin through the marked holes and mark them again on the copper side. Then cut the strips at the marked positions with a sharp hand held 6- or 7mm drill bit.<div>Some cuts have wirebridges going over them. Don't forget those!<br /><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1EEQwWMU0P1FZufe3JiDefyJYJPTenID5vClwQca5ymLi4Ly6ET2_1SfHoSGbhUJlKbNsAYQX3O-dLZCy62yGKXzeVUFlbvImXJgIj3MyXmU0X18SvdOJcG0mYy1J-BTzi1BGsJMcIVLIh6rv6XtlNke7HYhNcJLx7OFurZakTN0TulCJujkVVZuPKQHC/s4538/303%20VCF%20JJ%20v3%20-%20cuts%20and%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3024" data-original-width="4538" height="213" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1EEQwWMU0P1FZufe3JiDefyJYJPTenID5vClwQca5ymLi4Ly6ET2_1SfHoSGbhUJlKbNsAYQX3O-dLZCy62yGKXzeVUFlbvImXJgIj3MyXmU0X18SvdOJcG0mYy1J-BTzi1BGsJMcIVLIh6rv6XtlNke7HYhNcJLx7OFurZakTN0TulCJujkVVZuPKQHC/s320/303%20VCF%20JJ%20v3%20-%20cuts%20and%20wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><span style="color: red;"><b>Bill of materials:</b></span></div><div><span style="color: red;"><br /></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHdeHhxF3UrgT1hUqo4CrhbaVmdPF_0KFo1YhKSeVOht0siliPGlOtzFVsHsNmQ4TOx_Czs-OeTYjnENEjyBTyFVpTpyHmWO6LGCdrHyyeDYPovnePoJMawKl5KQzW2TRLaycpy2XeOaEHVB0ZT-TmEYgvcqY4MxUceNf6_LjxyCcXp4LUaiACYy42xgpQ/s860/303%20VCF%20V3%20Bill%20of%20Materials.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="430" data-original-width="860" height="160" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHdeHhxF3UrgT1hUqo4CrhbaVmdPF_0KFo1YhKSeVOht0siliPGlOtzFVsHsNmQ4TOx_Czs-OeTYjnENEjyBTyFVpTpyHmWO6LGCdrHyyeDYPovnePoJMawKl5KQzW2TRLaycpy2XeOaEHVB0ZT-TmEYgvcqY4MxUceNf6_LjxyCcXp4LUaiACYy42xgpQ/s320/303%20VCF%20V3%20Bill%20of%20Materials.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div><b><span style="color: red;">PICTURES:</span></b><br /><div style="text-align: left;">Here are some pictures of the build proces. This is from the old unrevised version so it's not completely the same as the layouts.:</div></div><div style="text-align: left;">Cuts and wirebridges done:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheIKllreA7Wb0w7GhHPw5mwk9LG3HdloS-Xv0Xv4iuVGj5Bnk9w1GqgnMZ4aijkkvkkruiP1oVBw0mEmYfl4hzGWlvFeXq3PF7wIRFAjbTXuyWfvarS24zwdjSjajb1r_xv9btsElNDLxMM0drEDVnqg3h2srBTSIiBpkYmGsdomC97OOZcAYhUG44ZiOC/s3928/303%20VCF%20cuts%20and%20wirebridges%20done.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2424" data-original-width="3928" height="197" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheIKllreA7Wb0w7GhHPw5mwk9LG3HdloS-Xv0Xv4iuVGj5Bnk9w1GqgnMZ4aijkkvkkruiP1oVBw0mEmYfl4hzGWlvFeXq3PF7wIRFAjbTXuyWfvarS24zwdjSjajb1r_xv9btsElNDLxMM0drEDVnqg3h2srBTSIiBpkYmGsdomC97OOZcAYhUG44ZiOC/s320/303%20VCF%20cuts%20and%20wirebridges%20done.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Everything is soldered in.<br /><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT_UfsLP5Vq13BejhEmxy4TBJ9CRl5vRiEci1voxNJin-47QHVHuVPMCffjkavEBwjW2nvieLmTrAY6A01ruzQ038RdIHscJasNYRW2y-PBm05OLYEFVUpSEV9PVRTaJB7tKT5-eYSoQIHfkGPmYnC1ac-A2o1O2-wiRxnp9bOxYNRi1zMBqakV8GQq2jq/s3592/303%20VCF%20stripboard%20done.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2340" data-original-width="3592" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT_UfsLP5Vq13BejhEmxy4TBJ9CRl5vRiEci1voxNJin-47QHVHuVPMCffjkavEBwjW2nvieLmTrAY6A01ruzQ038RdIHscJasNYRW2y-PBm05OLYEFVUpSEV9PVRTaJB7tKT5-eYSoQIHfkGPmYnC1ac-A2o1O2-wiRxnp9bOxYNRi1zMBqakV8GQq2jq/s320/303%20VCF%20stripboard%20done.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">Here's the design I made for the panel. Feel free to us it if you want.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJBlJxHbec8ETdcOfZ0anf490X0hBXQS4P6lK9NUipPPhQTd3QGrS9HbPUUBhkBj43J-6gh1MZwlU8XkvLmd_Hdp-cPLUKBlwMwDk0ayHNY3xpHA_RGlk4r4yvBTyGtw7ujuWg0ZkTTPxmt1zEMXQHXFWfh8lNL2KtHcnbN1pwc7_Pzti3tbs4TN_sS1TX/s3496/303%20Panel%20design%20V2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3496" data-original-width="2480" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJBlJxHbec8ETdcOfZ0anf490X0hBXQS4P6lK9NUipPPhQTd3QGrS9HbPUUBhkBj43J-6gh1MZwlU8XkvLmd_Hdp-cPLUKBlwMwDk0ayHNY3xpHA_RGlk4r4yvBTyGtw7ujuWg0ZkTTPxmt1zEMXQHXFWfh8lNL2KtHcnbN1pwc7_Pzti3tbs4TN_sS1TX/s320/303%20Panel%20design%20V2.jpg" width="227" /></a></div><div><br /></div>And here's how the panel came out:<div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkXhoN3onD2CxDSe_Cd0uQ6Vdl71McBDnMLobwhdf6tqASxlsey_Aa9n4ZSAnptFkeCm1e-YcOzNwY4GFkeqRDhST-PwgjT2tmo0ZnqVnDbcM_2bOV0d4fjQpOx8_0kh9-SpjCIDeJxQHhb0pT6-WfCEME0yYjFmkgrxl_Y0GdskK0nnqU6Bw6ewesN3bu/s2948/Panel%20ready.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2948" data-original-width="1658" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkXhoN3onD2CxDSe_Cd0uQ6Vdl71McBDnMLobwhdf6tqASxlsey_Aa9n4ZSAnptFkeCm1e-YcOzNwY4GFkeqRDhST-PwgjT2tmo0ZnqVnDbcM_2bOV0d4fjQpOx8_0kh9-SpjCIDeJxQHhb0pT6-WfCEME0yYjFmkgrxl_Y0GdskK0nnqU6Bw6ewesN3bu/s320/Panel%20ready.jpg" width="180" /></a></div><div><br /></div>You can see the colours don't come out as strong with clear waterslide paper as opposed to using white waterslide paper. But I like this effect. The design shouldn't be too overpowering I think.<br /><div><br /><div class="separator" style="clear: both; text-align: left;">Here's a look at the finished module:</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhycx20_JHIfpjgrZy8_pp4t3PvArzDdNbnElALstNMYNqvPj0KW9mezwjyBfgSKDX9MtFftF2laPkhRb0RHPt__h9iX2JszUf9cd8FIlYbsDKwzKvUqUKM_6X640RNJX7wZI6F6fkNpFO0YYEhqzbsKnoVYuXgk5uCEbJc4aXpxyNyppAePe-d_DkT13M/s3778/303%20finished%20module%20faceplate.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3778" data-original-width="2534" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhycx20_JHIfpjgrZy8_pp4t3PvArzDdNbnElALstNMYNqvPj0KW9mezwjyBfgSKDX9MtFftF2laPkhRb0RHPt__h9iX2JszUf9cd8FIlYbsDKwzKvUqUKM_6X640RNJX7wZI6F6fkNpFO0YYEhqzbsKnoVYuXgk5uCEbJc4aXpxyNyppAePe-d_DkT13M/s320/303%20finished%20module%20faceplate.jpg" width="215" /></a></div><br /><div class="separator" style="clear: both; text-align: left;">Side/rear view. I had built a version before this one but it didn't work but I re-used the panel I made so the mounting holes are not positioned where they need to be so that's why the M3 bolt is bent sideways.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3qukTE308aLF0-mEiVayAjPB4sVfdQsg0XLAiO3FvVGANGO-dcNTilW6AS5coUcubD4NKi1shyZafeCJvt7wSj-UORl_tbFe3yLTYFSrHqMe8Wdc5VrBQ8KCFF8L0Xv8phTSmqAHMTVLxgCzraijZLFbeCLV52VtmS-3x9y1QP-1cOyUHKD41hlxAYG5i/s3376/303%20finished%20module%20rear.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3376" data-original-width="2268" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3qukTE308aLF0-mEiVayAjPB4sVfdQsg0XLAiO3FvVGANGO-dcNTilW6AS5coUcubD4NKi1shyZafeCJvt7wSj-UORl_tbFe3yLTYFSrHqMe8Wdc5VrBQ8KCFF8L0Xv8phTSmqAHMTVLxgCzraijZLFbeCLV52VtmS-3x9y1QP-1cOyUHKD41hlxAYG5i/s320/303%20finished%20module%20rear.jpg" width="215" /></a></div><br /><div class="separator" style="clear: both; text-align: left;"><b><span style="color: red;">VIDEO DEMO:</span></b></div><div class="separator" style="clear: both; text-align: left;">This filter has that typical ladder filter quirck where if you turn the resonance up the volume goes down and you get less bass. Most ladder filters have this characteristic. The Moog ladderfilter does it and even the Doepfer A-103 VCF-6 does it.&nbsp;</div><div>Here's demo, trying to get that Acid sound using some of the tips from the YouTube short video below. I came close but it's not quite there. I had a slowly rising sinewave on the CV input and a short pulsing envelope, with just some decay and all the other parameters of the ADSR closed. Instead of an LFO I think an offset voltage alone would be better. You can hear it reaches that "eeeuuurrrghhh" sound as the LFO rises in voltage but then it gets too high and it starts to whistle more. I'm going to do more experiments, using the voltage processor and see where that gets me.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dyo56w_tx7NXuU2FrEcxtMlfIBIiDmCs9gRu4A25uXy-xxmiHzIbMCaepE-6pz6ANBKOcT6gyt9e90F3UvvHA' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div>Here's an other short test. Beside the envelope input I also had an offset voltage going into the CV input. That offset voltage came from the dual voltage processor to which I also had a sawtooth LFO connected. I set the processor in such a way that I always fed an offset voltage to the filter but the voltage would swing between about +2V to +4V. You can do this by raising the offset and then using the attenuverter to limit the maximum voltage. A very useful module to have in combination with this filter.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dwZ_a7ylHdsGNL0JIABYHS5F3yNAZaNpsjwmgnqYmoZh6q5OSd3niw6hyvTT3L6b7guiTkgcAk6alrxgmla_w' class='b-hbp-video b-uploaded' frameborder='0'></iframe></div><br /><div>Here's a YouTube short explaining how to get the characteristic 303 sound:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/D3GSBq8nzRo" width="320" youtube-src-id="D3GSBq8nzRo"></iframe></div><br /><div><br /></div><div class="separator" style="clear: both; text-align: left;"><b><span style="color: red;">Documentation:</span></b></div><div class="separator" style="clear: both; text-align: left;">Here's the webpage of Tim Stinchcombe about the <a href="https://www.timstinchcombe.co.uk/index.php?pge=diode2" target="_blank">TB303 ladder filter.</a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Here's Ian Fritz's original <a href="https://web.archive.org/web/20151002134800if_/http://home.comcast.net/~ijfritz/MiscProj/transmat001.pdf" target="_blank">article on transistor matching in PDF form</a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;">That's all for this one.</div><div class="separator" style="clear: both; text-align: left;">If you have any questions or remarks about this project then please put them in the comments below or post them in the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">special facebook group</a> for this website.</div></div><div><br /></div></div><div><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div>


guid: tag:blogger.com,1999:blog-8559314700259794131.post-2935339869522832224
title: Synthesizer Build part-67: KASSUTRONICS PRECISION ADSR.
author: Eddy Bergman
url: https://www.eddybergman.com/2025/04/Kassutronic-precision-adsr.html
feedurl: https://www.eddybergman.com/feeds/posts/default
content_mime_type: text/html
content:
<div style="text-align: left;">The best version of the 7555 based ADSR's on this website. This one uses precision rectifiers to eliminate the problems the previous versions have. This project is small enough for Eurorack and runs fine on dual 12V or 15V and is easy to build even for beginners.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">There are PCBs available for this ADSR (8V output version). See&nbsp;<a href="https://www.eddybergman.com/p/pcb-service.html" target="_blank">'PCB Service'</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;">This is another version of the two 7555 ADSR's you've already seen on this website. The previous ones by Yusynth and Rene Schmitz had the problem that, because of diode voltage drop, the envelope wouldn't get down to 0 Volt after each cycle. The diode in series with the release potmeter would stop conducting when the voltage dropped to the threshold of 700mV in case of a 1N4148 and around 300mV for Schottky diodes.</div><div style="text-align: left;">This ADSR eliminates that problem.</div><div style="text-align: left;">By using precision rectifiers made up of a diode inside the feedback loop of an opamp, you solve the problem of the 700mVolt remaining after the release cycle and so the ADSR not returning to 0 Volt after each cycle. The opamp now has that voltage drop in the feedback loop and compensates for it, effectively creating a perfect diode.</div><div style="text-align: left;">I tried to address the voltage drop problem in the Rene Schmitz version by using Schottky diodes that have a very low voltage drop of about 0.3 V (300mV) and that already helped a lot. This version lowers that even further although on my oscilloscope I could still measure a tiny bit of voltage left over but the majority of that was due to the capacitor I was using. It was about 90mV. I used a normal electrolytic capacitor for testing. I then tried a Tantalum capacitor and that lowered the offset to around 10 to 20mV. That's almost the noise floor so really no problem what so ever. It's 35 times better than using a 1N4148 in the Yusynth ADSR. The reason for this is transistor resistance. The Gate voltage, if switched by a transistor, never reaches zero because of transistor resistance. But this is such a low voltage that you can totally ignore it. So please don't go fretting about 20 thousandths of a Volt. 20mV is equal to 0V!!</div><div style="text-align: left;">Use a 1µF Tantalum capacitor like the schematic says. The slowest risetime you can create with 1µF is 1.2 seconds. If you want longer risetimes you need to connect two caps to a switch so you switch between low and high speeds. That's up to you. I didn't include that option in this project but it's very easy to implement.&nbsp;</div><div style="text-align: left;">If you want to read more about this ADSR then here's the link to the <a href="https://kassu2000.blogspot.com/2015/05/precision-adsr.html" target="_blank">Kassutronics webpage.</a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Variations on this design:</span></b></div><div style="text-align: left;"><span style="color: #fff2cc;">Before we begin I want to mention I recently added a version of this ADSR that can output up to +10V instead of up to +8V. I have schematics and layouts for that version at the bottom of this article.</span></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">SCHEMATIC</span></b></div><div style="text-align: left;">I made some changes to the design of this ADSR. For one, I don't like the high value resistors on the gate input. I always get problems with the gate pulse not getting through. So because the Rene Schmitz version works so well I copied the Gate/Trigger section from that ADSR and put it in this one too. It's practically the same circuit but with different resistor values.</div><div style="text-align: left;">I also changed the inverted output to an attenuverted output. I find that much more useful because you can play with the attenuverter while you're feeding the ADSR signal into the CV input of a filter and get all sorts of cool sounds from it. You can turn it into a normal output if you need an extra output. Much more versatile I think. The schematic below has all the changes I made included.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin8pKNOlQfBiGnOkNLCmRDhHW1MQhWX72_c0Hpds58yF5VNLuMgvMnxF62mrZFRPv16XuiY-QsO_77xTcg6gQDXOcy-gNxxQxc1nq8zrq7jvqSGuyepoLJOJwVnp2xVeEgykegXHlIHpia5k09OPgAH7kCSAqjKHChSbL2Y0Frh44d9_iitp3Ycfcbs5LM/s1436/Kassutronics%20Precision%20ADSR%20schematic%20EB%20version%203b.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1323" data-original-width="1436" height="295" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin8pKNOlQfBiGnOkNLCmRDhHW1MQhWX72_c0Hpds58yF5VNLuMgvMnxF62mrZFRPv16XuiY-QsO_77xTcg6gQDXOcy-gNxxQxc1nq8zrq7jvqSGuyepoLJOJwVnp2xVeEgykegXHlIHpia5k09OPgAH7kCSAqjKHChSbL2Y0Frh44d9_iitp3Ycfcbs5LM/s320/Kassutronics%20Precision%20ADSR%20schematic%20EB%20version%203b.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div>Eventhough I used BAT43 Schottky diodes for D1 and D2 in the layouts below, you can just put in 1N4148 diodes. The voltagedrop isn't important here and both diodes have the same switching speed of 5nSec. They are just used here as reverse voltage protection.<div><br /></div><div>Here's the KiCad version of the schematic. I'm teaching myself to work with KiCad and it's going very well. I taught myself in 3 days.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDfsogxGtDt6iAkJOy7Tg23757fvttKCdc9b3FZDBBsbuCSsHGul7ZvVVSTWr8iz3TwUhQfg5pidO_eFZKqivj2VGkG3ZUAs7IMYgBYLtdeCGZ97WJnk8jYEXLrytumHma_tkFmoCSlCMRSjLWSftbBnBJIfFEKKL3t1tW0k9Y4_RxDO3CwF-CdKVBRKi9/s1175/Kassutronics_ADSR_KiCad_Schematic.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="809" data-original-width="1175" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDfsogxGtDt6iAkJOy7Tg23757fvttKCdc9b3FZDBBsbuCSsHGul7ZvVVSTWr8iz3TwUhQfg5pidO_eFZKqivj2VGkG3ZUAs7IMYgBYLtdeCGZ97WJnk8jYEXLrytumHma_tkFmoCSlCMRSjLWSftbBnBJIfFEKKL3t1tW0k9Y4_RxDO3CwF-CdKVBRKi9/s320/Kassutronics_ADSR_KiCad_Schematic.jpg" width="320" /></a></div><div><div class="separator" style="clear: both; text-align: center;"><br /></div><b><span style="color: red;">LAYOUTS:</span></b><br /><div style="text-align: left;">Below are the layouts I made for this project. As always they are verified. I used them to build my ADSR and it worked rightaway. An other hole in one.&nbsp;</div><div style="text-align: left;">I alterred the layouts a little one day after posting this article in so far that I added a transistor to drive the LED to avoid pulling down the envelope voltage.&nbsp;</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Wiring:</span></b> (All potmeters viewed from the backside!) As you can see the potmeter wiring is a bit complicated looking so be accurate when wiring up the pots!&nbsp;</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyEe1XfZHG0eG3ByJixwjju4SqxiaWiCjdhyEDxXuoN_b2NxdHjWhU_NIOYHa0gfv17qRabd0Yu6IoPqXE5yz9aWo8x5oNRqUTO_I0FqdH9dGM8eGtUW3KxAGGhbSXZ4EiC5MXvyifO7gnt36-lL85O6jn5H4tW9IweXHpsnWoXx3t1LLyRorx34alMla5/s7729/01%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4913" data-original-width="7729" height="203" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyEe1XfZHG0eG3ByJixwjju4SqxiaWiCjdhyEDxXuoN_b2NxdHjWhU_NIOYHa0gfv17qRabd0Yu6IoPqXE5yz9aWo8x5oNRqUTO_I0FqdH9dGM8eGtUW3KxAGGhbSXZ4EiC5MXvyifO7gnt36-lL85O6jn5H4tW9IweXHpsnWoXx3t1LLyRorx34alMla5/s320/01%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20wiring.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Stripboard only:</span></b></div><div style="text-align: left;">If with testing you notice that the envelope doesn't come up when the Attack potmeter is fully closed then use a 330 Ω resistor in series with the Attack potmeter (R8) instead of the 100 Ω in the schematic. This is something I had to do with my build.&nbsp;</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi85LY1vGD8lOaaKRsIWThjGPMJm5VJzfZFOW0RvUN-yQyHJ2EYXA5Opzoc9IYVrEaOaMY0gVplhVToJ23rjMmpl3unPEnw0HbWqEUwX_8ALkgclMkR8IazBIGUXHK4ywaCebuks6cB6-mqRKIn-EKMCEVyIPr30GO6vn5kEgZ3eJbPEAxvKFYiogmWyCsR/s3697/02%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2737" data-original-width="3697" height="237" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi85LY1vGD8lOaaKRsIWThjGPMJm5VJzfZFOW0RvUN-yQyHJ2EYXA5Opzoc9IYVrEaOaMY0gVplhVToJ23rjMmpl3unPEnw0HbWqEUwX_8ALkgclMkR8IazBIGUXHK4ywaCebuks6cB6-mqRKIn-EKMCEVyIPr30GO6vn5kEgZ3eJbPEAxvKFYiogmWyCsR/s320/02%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20stripboard%20only.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">Cuts and wirebridges</span></b> seen from the component side.</div><div style="text-align: left;">You know the drill, mark the cuts on the component side, stick a pin through the marked holes and mark them again on the copper side and then cut on the marks.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTJ2W2632X6dcnWlRec3_gSyVbzBoeicTXeZJRtk9Nnm1GIFK6oC9snjgf1NbpIzRtwN91hHkLnCnfykJKqUGoXmE0FD-rNRKTZlpDU5fwuk-lkk_XOGBOtbzVZfADDLzm_MNkv40hz7JDSDHc8qtMtfTbdCgvWGoqW2JV0PeXz5ScIMJ7qyEsUgT71Sn7/s3983/03%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20cuts%20wirebridges.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2997" data-original-width="3983" height="241" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTJ2W2632X6dcnWlRec3_gSyVbzBoeicTXeZJRtk9Nnm1GIFK6oC9snjgf1NbpIzRtwN91hHkLnCnfykJKqUGoXmE0FD-rNRKTZlpDU5fwuk-lkk_XOGBOtbzVZfADDLzm_MNkv40hz7JDSDHc8qtMtfTbdCgvWGoqW2JV0PeXz5ScIMJ7qyEsUgT71Sn7/s320/03%20Kassutronics%20ADSR%20w%20Attvert%20v3%20-%20cuts%20wirebridges.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><span style="color: red;"><b>Here's the Bill of Materials.</b></span></div><div style="text-align: left;">Not every component is numbered exactly as in the schematic but most of the resistors are. Order a Tantalum capacitor for C3 1µF/35V. You can use any type of 7555 timer chip. I used the ICM7555. Don't use a normal NE555 though. It might work but they're not ideal. It needs to be a CMOS type.</div><div style="text-align: left;">As usual I didn't put any decoupling caps in but if you want to include it, there's room enough on the stripboard. You can put two 100nF caps; one from plus to ground and one from ground to minus. If you feel you need extra stabilization put some 10µF caps over the power rails too. That's up to you, the ADSR works fine without them.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZs9d-vcm2RVlydwGMPr318OfDO92VVcNKsp7B1UuHfuzH-njpEfeUj1NVYoTvQ7b6i45xyLitK3pDPD7l8jyujpCN0poebl8gxq7BKp4Rlzs98GIztAdHMqe53u8aDTHgCNM5i01l6GTWZkSZV4kM6usXNP3RpqkEeYgd6ABI35tqdCcu5LUBs12KZJZQ/s833/04%20Kassutronics%20Prec%20ADSR%20v3%20BOM.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="429" data-original-width="833" height="165" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZs9d-vcm2RVlydwGMPr318OfDO92VVcNKsp7B1UuHfuzH-njpEfeUj1NVYoTvQ7b6i45xyLitK3pDPD7l8jyujpCN0poebl8gxq7BKp4Rlzs98GIztAdHMqe53u8aDTHgCNM5i01l6GTWZkSZV4kM6usXNP3RpqkEeYgd6ABI35tqdCcu5LUBs12KZJZQ/s320/04%20Kassutronics%20Prec%20ADSR%20v3%20BOM.JPG" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;"><b><span style="color: red;">PICTURES and test results:</span></b></div><div style="text-align: left;">This ADSR has a very fast risetime. I measured risetimes of 550µSeconds! The output amplitude of the envelope has a maximum voltage of 8.4 Volt when you run this on a +/-12 Volt power supply. Maximum Sustain level is 8 Volts. This is determined by pin 6 of the 7555 (Threshold) which stops charging the capacitor at 2/3rds of VDD. (+8V). The timer stops and the capacitor is discharged through the Decay potmeter and U2-D and D4 to the Sustain level. The output will stay at the Sustain level until the Gate input stops. Then the capacitor will discharge through the Release potmeter, U2-A and D3 to 0V. As I mentioned before, the maximum risetime of the Attack phase is 1.2 seconds with a 1µF cap. If you need longer times you can put a 1µF and a 10µF on a switch and connect that to the stripboard, so you have a choise. The fast times sound amazing though when used on filters (especially the 303 filter).</div><div style="text-align: left;">Here are some pictures of the finished product. They were taken in the test phase so some components that are on the layout are not in these pictures (like the LED driver transistor for instance).</div><div style="text-align: left;"><span style="color: #fff2cc;">If you have problems with the ADSR not triggering correctly with certain equipment, try putting a pulldown resistor on the trigger/gate input. A 10K should work. This ADSR has a high input impedance so a pulldown resistor can be a solution for problems like that.</span></div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEE3bLE5xS8YT3YnfZSKg5HBtS-aPtkPC80D2qA14Zbc5bdvm93m-jG0r-S2qKUi1BOFHrnIg3ZEINp8kdgg2INXhFK66paKbJl_DfVcAnCAfdV2elk_bdY8bHEdWjhIDzF8H62kVDbR3sSfXeOfFy3TDRPnQgXqEgpUgLlOUnTHVX8HOGVbNlizf6fAqk/s4000/Finished%20module%20comp%20side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEE3bLE5xS8YT3YnfZSKg5HBtS-aPtkPC80D2qA14Zbc5bdvm93m-jG0r-S2qKUi1BOFHrnIg3ZEINp8kdgg2INXhFK66paKbJl_DfVcAnCAfdV2elk_bdY8bHEdWjhIDzF8H62kVDbR3sSfXeOfFy3TDRPnQgXqEgpUgLlOUnTHVX8HOGVbNlizf6fAqk/s320/Finished%20module%20comp%20side.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsr_dQtHcNBnIRFeD3-eRwmrfbaOlGgURaB54a7qeZAjW3M92yC5YOwbJdXaCI-Uwu-_g6nYS7w_TbIn_XCyvMPbyVM02PEMyPEO-4iN5l9ZlhWfSgRVid_0F2GsKlbUVIp5n47B-8xkb3vIAZct8i19dKm02oYzuItWlJR5VuT3VOHrU7rt2pojSHQH4z/s4000/Finished%20module%20copper%20side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsr_dQtHcNBnIRFeD3-eRwmrfbaOlGgURaB54a7qeZAjW3M92yC5YOwbJdXaCI-Uwu-_g6nYS7w_TbIn_XCyvMPbyVM02PEMyPEO-4iN5l9ZlhWfSgRVid_0F2GsKlbUVIp5n47B-8xkb3vIAZct8i19dKm02oYzuItWlJR5VuT3VOHrU7rt2pojSHQH4z/s320/Finished%20module%20copper%20side.jpg" width="320" /></a></div><br /><div style="text-align: left;">I used the same faceplate as I used for my previous 7555 ADSR's. I just exchanged the stripboard for this one and wired everything up again.</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvVirtYkNHD21bhyq8FUls8pQAqQHcPmxpQnNGSCXv9gxguWJWzPVK1W1xTYurYFaTzal1bHNLcxvmNEVHn4lVzjMyfaa4QjPZWIo79Hy6EePmwgXYUqjaZaBnFU-68eOco0zsqUn4w-mqa2psZnoEYN3UpEpZ-oAk8oM_SMadjDA0aUwOdXCauyf8TLGF/s4000/Kassutronics%20ADSR%20panel.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvVirtYkNHD21bhyq8FUls8pQAqQHcPmxpQnNGSCXv9gxguWJWzPVK1W1xTYurYFaTzal1bHNLcxvmNEVHn4lVzjMyfaa4QjPZWIo79Hy6EePmwgXYUqjaZaBnFU-68eOco0zsqUn4w-mqa2psZnoEYN3UpEpZ-oAk8oM_SMadjDA0aUwOdXCauyf8TLGF/s320/Kassutronics%20ADSR%20panel.jpg" width="240" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div style="text-align: left;">Here are some screenshots from the oscilloscope. The first one shows the extremely fast risetime of this ADSR/ With Attack set to zero you can get risetimes of 550µSeconds. This with a Tantalum cap and a 330 Ω resistor in series with the Attack potmeter, instead of 100 Ω in the schematic.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjheT_GPiW7G2JwOZULxv0ShbImzSYe2LfFUEjALE668niJZMToSPIEAJO8xdMJ_AHqzGbDV1OdvvEt7iErs3_Rqf3dllWEQScHMib8rFFXgv6ZHc4itGxN2MZsxRXStJUxogI_fa6E80UyA-iuHOc_cu4azJeU_w6YJQ35IS4IN8LTqdEbHH6mdZ4qb28a/s800/550mS%20risetime.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjheT_GPiW7G2JwOZULxv0ShbImzSYe2LfFUEjALE668niJZMToSPIEAJO8xdMJ_AHqzGbDV1OdvvEt7iErs3_Rqf3dllWEQScHMib8rFFXgv6ZHc4itGxN2MZsxRXStJUxogI_fa6E80UyA-iuHOc_cu4azJeU_w6YJQ35IS4IN8LTqdEbHH6mdZ4qb28a/s320/550mS%20risetime.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;">Below is a screenshot of the quickest pulse I could get with all potmeters closed. You can see the risetime is the same as above, about 550µSec and the releasetime is faster because it only has 100 Ω in series. It's about 400µSec.Total time is 992µSec. So you could create a waveform with a top frequency of 1kHz with this ADSR.</div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlsMQaTin66ckXsbLXwuR-Es-eDaJrfaY2FH_tNgBp2-3ziGsz_DYJv7kEGeNWWWHc1_AOqNeX-xWqHqahqxgyS_aaV2pJscrnXVC9o0bNCrXtKJDV8iPFXNLvFVnqycdPQNMiaEleFgg0KDnDpubmS5l6vNWHasnaumD7OJC1_mBRvCvNIKB7j0m1TxnR/s800/Quickest%20Pulse%20time.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlsMQaTin66ckXsbLXwuR-Es-eDaJrfaY2FH_tNgBp2-3ziGsz_DYJv7kEGeNWWWHc1_AOqNeX-xWqHqahqxgyS_aaV2pJscrnXVC9o0bNCrXtKJDV8iPFXNLvFVnqycdPQNMiaEleFgg0KDnDpubmS5l6vNWHasnaumD7OJC1_mBRvCvNIKB7j0m1TxnR/s320/Quickest%20Pulse%20time.jpg" width="320" /></a></div><br /><div style="text-align: left;">Below here is the normal and inverted output. The voltages indicated by the scope are a bit lower because I had the LED connected straight to the output. I now have the LED driven by a transistor which means no voltage pull-down so the real maximum voltage is about 8.4 Volt. Max sustain voltage is 8 Volt as is the case with all ADSR's that use a 7555 and are run on +12V because that voltage is 2/3rds the voltage of the positive powerrails. If you run it on +/-15V it would be +10V.</div><div style="text-align: left;">The sustain is actually very stable because of the use of precision rectifiers. There is no leakage of voltage from the sustain stage.</div><div style="text-align: left;"><span>If you want to change the output voltage to 10V then checkout the rest of this article below where we change the output opamp from a voltage follower to a non inverting amplifier with a gain of 1.25</span></div><div style="text-align: left;"><br /></div></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVT6xuuOBMPn2qFcK5JEZlNunF2s7QavKISLZIBYlMDxqkeBPjGht3SGOM4SdVlLC7sCruF-HhnxYsOW7i3gVSX23u8Vc4x2bhDBVJbFnVuGh18S018zb9tMEP-AN6hrVvpVVNpQstZSsUOz8bGMy8ura1JPd8t0gcJniqX7IY9t7n3UQLgihuCLGcytT2/s800/Normal%20and%20Inverted%20output.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="480" data-original-width="800" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVT6xuuOBMPn2qFcK5JEZlNunF2s7QavKISLZIBYlMDxqkeBPjGht3SGOM4SdVlLC7sCruF-HhnxYsOW7i3gVSX23u8Vc4x2bhDBVJbFnVuGh18S018zb9tMEP-AN6hrVvpVVNpQstZSsUOz8bGMy8ura1JPd8t0gcJniqX7IY9t7n3UQLgihuCLGcytT2/s320/Normal%20and%20Inverted%20output.jpg" width="320" /></a></div><br /><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="color: #fcff01; font-size: large;"><b>ENLARGING THE OUTPUT VOLTAGE TO +10V</b></span></div><div style="text-align: left;">I thought about how to up the output voltage of this ADSR to +10V while running it on +/-12V and I asked ChatGPT and the best method is to put a bit of gain in the output opamp. So turning it from a voltage follower (or buffer) into a non-inverting amplifier with a gain of 1.25. Naturally the attenuverter needs to be re-routed too in that case, at least in the schematic. It turned out I didn't need to change the attenuverter connection in the layouts because it was already connected to pin 8. I made an additional schematic for the new setup:</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaofy6fKthNcdIa_tGfj68DIvnZKJDqaxjH_vyQb16ky94GlM0I1W4PksgCC1LGXhWxM0GNBR9AZlKCrRVlDEbEGWpU1HGsAeF5P8EfdupA7UVMNgCmJkujCOEmfBtkALEVpmotFZeCTdbUx9lnARhv06xsY0AvOqXppvD6pZ7qYBQcCCeN9kybL7DQeFH/s1436/Kassutronics%20Precision%20ADSR%20schematic%20EB%20version%203d%2010V%20out.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1323" data-original-width="1436" height="295" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaofy6fKthNcdIa_tGfj68DIvnZKJDqaxjH_vyQb16ky94GlM0I1W4PksgCC1LGXhWxM0GNBR9AZlKCrRVlDEbEGWpU1HGsAeF5P8EfdupA7UVMNgCmJkujCOEmfBtkALEVpmotFZeCTdbUx9lnARhv06xsY0AvOqXppvD6pZ7qYBQcCCeN9kybL7DQeFH/s320/Kassutronics%20Precision%20ADSR%20schematic%20EB%20version%203d%2010V%20out.jpg" width="320" /></a></div></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Gain of a non-inverting opamp: Gain= 1+(Rfeedback/Rground) = 1+(12/47) = 1.2553</div><div style="text-align: left;"><br /></div><div style="text-align: left;">I made some layouts for this version too. Really the only changes to make were to take out the wirebridge over pins 8 and 9 of the TL074 and putting in a 12K resistor instead and adding a 47K resistor from pin 9 to ground. That's all. So the cuts and wirebridges layout I posted earlier can also be used here except to leave out that wirebridge over pins 8 and 9.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">Wiring:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTzggVGYisF5L3qN_Ho8zsc0dJF-n7eH2O8w9Sv8WxWUsvp5_-A78tKP6NXHgGup_osu9OgZmxItMQJKOAmDQuNPDzeMHKb3lm-rOeQBGK9WtaXFjpCda1LuZBnGWZxz-9Aj_x5mbIS9RDdAi2kA44tSPsCAY5ejfI8Xh_H5_axc1D6e90OQp91jGPeH3_/s6361/Kassutronics%20ADSR%20w%20Attvert%20v3%2010V%20-%20wiring.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4019" data-original-width="6361" height="202" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTzggVGYisF5L3qN_Ho8zsc0dJF-n7eH2O8w9Sv8WxWUsvp5_-A78tKP6NXHgGup_osu9OgZmxItMQJKOAmDQuNPDzeMHKb3lm-rOeQBGK9WtaXFjpCda1LuZBnGWZxz-9Aj_x5mbIS9RDdAi2kA44tSPsCAY5ejfI8Xh_H5_axc1D6e90OQp91jGPeH3_/s320/Kassutronics%20ADSR%20w%20Attvert%20v3%2010V%20-%20wiring.jpg" width="320" /></a></div><br /><div style="text-align: left;">Stripboard Only:</div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzxm_3wqpeTuFZ48V9hvsWJ-i1aziALT2M1jyxdrJQnmkCsgAaApKYKL6Gw6kDaB7H7jMozHW8HYrEbOIwocH_L88PRuEWfLGR4ZAgW8THT8fki1cK9VrEC0ERjUGHF0PQmOjBaqHA13r9NLzGXlZh_FFKy3Or6Q24rdtS-Bzvg3HDB5vSdMCOtK_R8dVI/s5000/Kassutronics%20ADSR%20w%20Attvert%20v3%2010V%20-%20stripboard%20only.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3561" data-original-width="5000" height="228" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzxm_3wqpeTuFZ48V9hvsWJ-i1aziALT2M1jyxdrJQnmkCsgAaApKYKL6Gw6kDaB7H7jMozHW8HYrEbOIwocH_L88PRuEWfLGR4ZAgW8THT8fki1cK9VrEC0ERjUGHF0PQmOjBaqHA13r9NLzGXlZh_FFKy3Or6Q24rdtS-Bzvg3HDB5vSdMCOtK_R8dVI/s320/Kassutronics%20ADSR%20w%20Attvert%20v3%2010V%20-%20stripboard%20only.jpg" width="320" /></a></div><br /><div style="text-align: left;">Let me mention that these layouts have not yet been verified but I don't see why it shouldn't work. If you built this version will you please contact me with the results you're getting so I can verify this layout. Thank you! (I've had confirmation that the schematic works, so the layout should work too.)</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div></div><div><div style="text-align: left;">TIP: using your ADSR as a VCO. Send the squarewave output of a VCO to the Gate input of the ADSR. Now your ADSR acts as a VCO and with the Attack and Decay you can shape your own wave. It's a trick used in Psy-Trance Techno music. This ADSR is fast enough to do this. I tried it and it sounds pretty cool when you then input it into a filter.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">There is one more ADSR design that tries to really come down to zero volts after each cycle and that is the ADSR PRO by Davor Slamnig. <a href="https://dslamnig.wordpress.com/content/electronic/7555-adsr-pro/" target="_blank">You can visit his website by clicking here.</a></div><div style="text-align: left;">But really, the Kassutronics design is good enough and you're not going to notice any difference in practise so don't bother.</div><div style="text-align: left;"><br /></div><div style="text-align: left;">If you have any questions or remarks about this project then please put them in the comments below. Comments are moderated and don't appear straightaway!</div><div style="text-align: left;">You can also post your questions on the <a href="https://www.facebook.com/groups/325860521842129" target="_blank">special facebook group</a> for this website.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><div><b><span style="color: red;">PLEASE CONSIDER DONATING.</span></b></div><div>If you find this content helpful, please consider donating to keep this website in the air and to contribute to future projects. There's a Ko-Fi donation button underneath the main menu if you're on a PC or Mac. Otherwise use this&nbsp;<a href="https://paypal.me/ModularEddy" target="_blank">PayPal link</a>&nbsp;to cut out the middle man. Thank you very much for your help!</div></div></div><br />


