Doc Sketchy Frequency Shifter, Part 1: Explanation Doc Sketchy 2020-06-02 | In this video, I explain what a Bode frequency shifter does, and demonstrate each of the component parts of my design. In a second video, I will actually demonstrate the module.
Doc Sketchy Builds the LFO He Laid Out Before Doc Sketchy 2026-05-27 | In this third and final video of the series, I build and test the LFO circuit board that I laid out in the previous two videos. (If you have watched a version of this video already, please be aware that I erased the video and reloaded it, because I had forgotten to include about a minute of footage in that earlier version.)
Doc Sketchy Actually Does the Full LFO Layout Doc Sketchy 2026-05-13 | In this video, I actually show the full layout of the LFO circuit that was only partially shown in the previous video from May 8, 2026. I will show the full build of this PCB, from transferring to etching to drilling to tinning to stuffing to soldering to circuit testing, in the next video.
Doc Sketchy Lays Out a PCB in Excel 2003 Doc Sketchy 2026-05-08 | In this video (Part 1 of 2), I show how I lay out printed circuit boards using Excel 2003 (running in Windows XP). I show how I set up the spreadsheet, make graphical parts, follow the schematic to construct the layout, generate the traces and pads, and finally create the image to transfer to the PCB blank. The circuit I lay out is a Korg-inspired shape-shifting LFO. In part 2 of the series (which I hope to upload in the next few days), I will actually make the PCB that I have laid out here -- printing, transferring, etching, drilling, tinning, stuffing, and testing. In this way, you will have the complete picture of how Doc Sketchy makes his famous PCBs.In order to keep this video to a reasonable length, I have not shown the entire process of laying out the circuit from the schematic. If you would like to see that entire process, please let me know in the comments, and I will post another video just showing the entire layout process (getting all of the parts connected, and then tightening up the layout to save space).
Sketchy Labs DS-3100 Fully Polyphonic Synthesizer, Part 1: The Beast Doc Sketchy 2026-04-06 | After stringing along my followers on Mod Wiggler, I have finally made a video demonstrating the core circuitry of my polyphonic synthesizer project, the DS-3100 -- my homage to the Korg PS-3100, but done in Doc Sketchy style, with PCBs laid out in Excel, fully handmade and based entirely on my own original circuitry.This is a pretty long video, but I hope you enjoy it. Please leave any questions or suggestions in the comments -- I will read and respond to every one.
Sketchy Labs New Folding Quantizer Doc Sketchy 2023-08-19 | This is the follow-up to the original Folding Quantizer video I posted on 19 September 2020. In this new video, I show the new module, which is based on the same concept as the previous quantizer, but now includes scale select and mode transpose functions.I will be offering these for sale (initially in Moog format only). If you think you might want one, please contact me (Dr. Sketch-n-Etch) on Mod Wiggler, and we'll set you up.
Sketchy Labs MFOS Rotary Sequencer Doc Sketchy 2023-04-04 | I finally decided to build one of these Music From Outer Space rotary sequencers a la Thomas Henry. The main innovation here is that I have eliminated all of the pot and LED panel wiring, which was a super-massive effort in the original builds. There is still a significant amount of wiring in this build, but nothing like the original. Also, I have created my own layouts of the circuit boards.Once again, apologies that my videography skills have not really improved since I've been away. Also, apologies to Boards of Canada.Finally, as I mention in the video, I'm not really prepared to build these for other people at this time, because it is a significant undertaking. That may change, though, especially if I can tighten up the wiring situation a little bit more.
Sketchy Labs ASR II (Prototype) Demo Doc Sketchy 2021-09-28 | Here is a short video demonstrating the latest iteration of my Analog Shift Register module in 8 HP eurorack format, the ASR II. This one has lots of extra features, including voltage controlled LOAD/LOOP and SHIFT/BYPASS switches (which are gated by 2V gate signals), a manual FREEZE/TRIGGER switch, and a GATE OUT jack which sends the clock and/or the switch triggers out as a buffered 5V gate signal.I will be offering these in the near future, and of course, they will have beautiful professionally made aluminum panels from Metalphoto, just like the Freak Shift. In the meantime, enjoy this little video, and if you have any suggestions for changes, please feel free to leave a comment, or contact me on Mod Wiggler.
Doc Sketchy Frequency Shifter, Part 4: New Freak Shift Lite Doc Sketchy 2021-02-05 | Here's a new version of the Doc Sketchy frequency shifter, called the "Freak Shift" -- it is a "lite" version, because it has no oscillator of its own. It has a second Dome filter (phase displacement network) for generating quadrature from any external VCO. It also has alternative inputs for externally supplied quadrature waveforms. Of course, you can put whatever you want into these inputs.... Enjoy!
Doc Sketchy Folding Quantizer Doc Sketchy 2020-09-19 | In this video I demonstrate my latest project, the Folding Quantizer. This is a quantizer which generates 128 steps of 83.33mV each, intended to generate semitones in a 1V/octave synthesizer system. It is based on a folding flash ADC, so there are no clocks, no ramps, no counters, no latches -- just real-time quantizing. Also, there are only TL07X opamps, an LM336Z5 5V reference, two trimpots, and two CD4070 ICs, in addition to a pile of resistors and some stability capacitors, so it is a very inexpensive build. Plus, as an added bonus, you get a smokin' hot view of my fat belly near the end, so... Enjoy!
Doc Sketchy Frequency Shifter, Part 3: Classy New Build and Lissajous Trick Doc Sketchy 2020-06-12 | This is the final frequency shifter video (I promise), at least for now. In this one, I show off my new build (Look ma, no wires! OK, just a few wires, but they're really short!) and show you a neato trick (some might even say it's keen) that you can do with Lissajous figures if you have an oscilloscope and another sinewave oscillator.I forgot to mention in the video, but those fabulous Lissajous figures are obtained by feeding a sine wave (from my homemade Rubicon) into the INPUT, and then taking the SUM and DIFF outputs to the two channels of the oscilloscope (in X/Y mode, of course). To get the different shapes, I'm flipping the waveform switches on the frequency shifter.
Doc Sketchy Frequency Shifter, Part 2: Demonstration Doc Sketchy 2020-06-03 | Here's the Demonstration part of the video for your viewing and listening pleasure. I didn't even demonstrate the various FM options of the shifter. I'll have to figure out something for that later. I'm still learning how to use this thing (obviously, if you watch the video).For the last bit of the video, it would have been better had I taken the audio directly from the mixer rather than ambient into the phone, since you can hear my unaltered voice along with the shifted version. However, hopefully you get the picture. Maybe, one of these days, I'll make a more accomplished video (but probably not).
Doc Sketchy 5U Dr. Octature 4-Pole Filter and Octature LFO Doc Sketchy 2020-05-25 | This is my new build of the Dr. Octature filter in 5U format, in my new style using a Panel Board to eliminate nearly all panel wiring, and a "Translator Board" to connect the Panel Board to the main Circuit Board. I am in the process of rebuilding all of my favorite modules, and a few new ones (look out for a 5U Quad Function Generator video, coming very soon). This module still has wired jacks (and 8 LEDs associated with the output jacks) but I will be modifying it soon with PCB-mounted jacks and LEDs. When that is done I will post pictures on my thread in Muff Wiggler, so watch out for that.So, this video is actually three separate clips stuck together. The first one is about 4 minutes, the second one is about 4 minutes (and really sucks), and the last one is about 2 minutes (and is pretty good), so please watch to the end.Finally, sorry, this one is also in Portrait format -- I keep forgetting to turn my phone sideways.
Doc Sketchy Quad Function Generator in Serge 4U Format Doc Sketchy 2020-04-25 | A demonstration of my Serge-4U-format Quad Function Generator, based on the Intellijel Quadra + Expander.This unit is part of a larger Serge 4U format modular being assembled in England by Loudest Warning, who is also organizing the panel.In this video I demonstrate a few basic patches. If you want to learn more about how this module works, I suggest the Intellijel Quadra Tutorial video -- this module is based on the same circuitry as the Intellijel Quadra and Expander, which I designed back in 2012.Also, sorry I forgot to turn the phone at 90 degrees, so this video is in Portrait format. I'll try to do better next time.
Voltage Controlled Morphing LFO from Doc Sketchy Doc Sketchy 2020-02-20 | As promised on the SDIY site, here is a brief video showing the circuit I designed and built over the last two days to achieve true voltage controlled morphing of saw-to-triangle-to ramp in a tri-square LFO. This same technique could also be applied to a tricore VCO of the "Dixie" type, which is also a tri-square oscillator.You may notice a slight frequency mismatch between saw and ramp -- this is because there is a trimmer which is not perfectly trimmed. I'm sure there will be more discussion on SDIY, so I'll leave it at that.Enjoy!
Doc Sketchy 8-Channel Scanner Doc Sketchy 2019-01-02 | Here is a very brief demo of my new 8-channel scanner. This module has been through an extensive re-design to eliminate digital switching noise, and I am happy to report that the switching is now perfectly noiseless. I had to abandon the idea of using 8-channel multiplexers and instead go with analog SPST switches. Another positive aspect of this change is that it made it practical to add channel-indicating LEDs, which fade from one channel to the next just like the audio. If anyone wants one of these beasties, please PM me on Muff Wiggler (I'm Dr. Sketch-n-Etch, in case you didn't know).
Doc Sketchy 5 channel scanner Doc Sketchy 2018-10-01 | This is the same board I showed in the last video, but with one tiny kludge, I've made it a 5-channel scanner (rather than 4). I've also installed it behind a 5U panel. I normalled input 5 to input 1, so if nothing is plugged into input 5, it will function exactly as before -- a 4-channel scanner with channel 1 at both top and bottom. This is better for sawtooth CV. For triangle or sine CV, 5 channels are better. If another input is left unplugged, that channel will just be ground. I forgot to show it, but this also scans nicely at audio rates, and gives some pretty strange waveforms.
Doc Sketchy New Simpler Morpher Circuit Doc Sketchy 2018-09-17 | This is a morphing circuit for four inputs. It takes a control input from -5V to +5V, and scans the inputs 1-2-3-4-1. Having 1 at the top of the scan has certain advantages, in that feeding a sawtooth wave gives smooth morphing in a 1-2-3-4-1-2-3-4 pattern, with equal time given to each waveform. The intention of this circuit was to mimic the action of the Moog Voyager waveform morpher. This circuit uses about half the parts of my original Interpolating Scanner. It isn't quite as versatile as that circuit, but much simpler to build and use. If you want one, drop me a PM on Muff Wiggler.
Doc Sketchy Dual Multiplying Modulator Doc Sketchy 2018-05-18 | A quick demo of my dual multiplying modulator module. This patch involves 3 VCOs fed 1V/octave inputs from the three channels of an Analog Shift Register. The ASR is triggered by the keyboard and takes the keyboard CV as the input. One VCO is fed to the X input of the first multiplying modulator (which is in balanced, 4-quadrant mode), and the second VCO is fed to the Y input of that multiplier. The output of that modulator is fed to the X input of the second modulator, and the third VCO is fed to the Y input of that modulator, which is in +2-quadrant mode. The result is a very rich ring-mod/sample-&-hold type of sound.As with everything else, I can build one of these for anyone who wants one. Send me a PM on Muff Wiggler (Dr. Sketch-n-Etch).
Doc Sketchy Eurorack ASR Doc Sketchy 2018-04-15 | This is the Eurorack version of the Sketchy Labs Analog Shift Register, handmade in Doc Sketchy style. PM me on Muffs if you want one.
Doc Sketchy ASR Demo Doc Sketchy 2018-03-10 | Here's a little video of my ASR module. This is my improved version of the CGS (Cat Girl Synth) ASR from Ken Stone. I have added some extra useful features, such as Shift/Bypass switches and a Load/Loop switch, which is pretty fun to use. I've also added an input attenuator, which to me is crucial. I put a new PCB that I had just stuffed for a customer into my existing panel to test. I found that it was really drifty (like, portamento drifty) -- the culprit: a dodgy LF444 opamp used for the S&H buffers. I bought some LF444s at a local shop (originally sourced from Digikey) and they are all crap (either defective or counterfeit) -- I had forgotten. Anyway, I replaced it with a TL064, and there is no drift at all. I'm also using 100n film caps, so those are large enough to avoid obvious drift if the input bias current of the opamps is reasonably low.
Doc Sketchy Dual Interpolating Scanner Demo Doc Sketchy 2018-03-10 | Here is the dual scanner, all put together and ready to send to its lucky buyer. I'm feeding it with the outputs of 4 VCOs, with two up-octave outputs into inputs 5 and 6, all tuned to a chord. Here I'm mostly playing with the switch that selects either two independent 4-channel scanners or one 8-channel scanner. It all works perfectly -- I just wish those little pots were a bit further apart. As usual, boards, bare or stuffed, and complete modules are available. Just ask (preferably on Muffwiggler).
Doc Sketchy Interpolating Scanner Demo Doc Sketchy 2017-10-27 | Here is the second demo of my new interpolating scanner circuit, with the improvements suggested by the Muff Wiggler beta testing team. I'd still like to figure out how to get the CV to maintain a constant range as the Width pot is adjusted, but I haven't so far. In any case, the Fader and Width pots are doing exactly what I want them to do.
