Sketchy Labs DS-3100 Fully Polyphonic Synthesizer, Part 1: The Beast

video upload by Doc Sketchy

"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."

Sketchy Labs Freak Shift Eurorack Module [Demo #1]

video upload by gstormelectro

"Audio + Video by G-Storm Electro c. 2021

Today I am auditioning the Sketchy Labs Freak Shift module.
The design is specially derived from the Bode Frequency Shifter.
There are literally sweet spots at every turn of the pots on this one.
In this video I'll briefly discuss this module and patch up some wierd sounds.
The focus is on demonstrating a range of evolving sounds of the frequency shifter.
I'll endeavor to make something more musical using the Freak Shift in a future video.
This video is not sponsored or endorsed by the Doc Sketchy.

0:00 Intro and brief discussion of patching
0:54 LFO as Mod input for phaser type sounds
1:24 Using 2 LFOs for Sine/Cosine modulation
2:55 VCO as Mod input for Frequency Shift sounds
4:48 Sum/Diff outputs for Stereo Spread
8:48 LFO modulating the AUX

Audio VCO | Pittsburgh Primary Oscillator
Modulation VCO | Cre8audio Capt'n Big-O
LFO Modulation | XAOC Batumi

Recorded direct to Tascam DR-05.
No additional effects or processing used."

**LISTEN/DOWNLOAD** http://soundcloud.com/gstormelectro
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Doc Sketchy DIY Videos

Published on Mar 9, 2018 docsketchy

This one in via John L Rice.

Doctor Sketchy is David G. Dixon, who designed a few Intellijel modules. Check out the David Dixon label for some of his previous creations.

Playlist:

1. Doc Sketchy ASR Demo

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.

2. Doc Sketchy Dual Interpolating Scanner Demo

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).

3. Doc Sketchy Interpolating Scanner Demo

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.