Designs for my Eurorack synthesizer modules

My modular synthesizer designs are shared in this repository.

Please note that I am a hobbyist, not a trained electronics engineer! These designs are not perfect. The modules work for me, but I can’t promise they’ll work for everyone who builds them.

These designs are shared as open source. See the license details in each project and source file.

– Len

General Info

Front Panels — How I make the front panels for my modules

Component Selection — Some notes on which parts to use when building these modules

Eurorack Bus CV and Gate — Spaghetti reduction

Firmware Programming — How to program the firmware onto the microcontrollers in some modules

Discussions — Forum for questions, comments, and conversations


These are the modules that I have built so far:

VCF-SV — State-variable filter module

Adder — Unity-gain mixer / precision adder

FX — Digital effects module

Attenuverter — Dual attenuverter module

VCF-4P — 4-pole lowpass filter module

Mixer1 — Small mixer module

Mixer2 — Dual mixer module

Buff-Mult — Buffered multiples

Bus-Driver — Driver module for Eurorack bus CV & gate signals

VCA-4 — Quad exponential VCA

Audiout — Audio output module

VCO-2131 — Analog VCO based on the SSI2131 chip

Envelope2 — Dual ADSR envelope module, microcontroller-based

Wavefolder — Dual analog wavefolder module

LFO-DigiVC — Voltage-controlled LFO, microcontroller-based

Noise-SH — Noise, sample-and-hold, and trigger clock, all in one module

Not Modules

Power-Supply — Eurorack power supply using a laptop charger

Cable Hanger — Simple desk-mounted patch cable rack

Creative Commons Licence
© 2022 Len Popp
This work is licensed under a Creative Commons Attribution 4.0 International License.