This is a Kosmo format synth module based on Ken Stone's CGS [https://sdiy.info/wiki/CGS_active_real_ring_modulator](Active Real Ring Modulator).

Main difference with Stone's original are:

• The instrument preamplifier was omitted
• Transformer footprints are for the TY-141P instead of the less available MO222
• Final stage input resistor is decreased to 10k, output resistor is increased to 1k, and a 100k pulldown is added on the output.

11.5 mA +12 V, 11.5 mA -12 V

• Schematic
• PCB layout: front, back
• BOM
• Build notes
• Blog post

• https://github.com/holmesrichards/arrm

This repo uses submodules aoKicad and Kosmo_panel, which provide needed libaries for KiCad. To clone:

git clone [email protected]:holmesrichards/arrm.git
git submodule init
git submodule update

Alternatively do

git clone --recurse-submodules [email protected]:holmesrichards/arrm.git

Or if you download the repository as a zip file, you must also click on the "aoKicad" and "Kosmo_panel" links on the GitHub page (they'll have "@ something" after them) and download them as separate zip files which you can unzip into this repo's aoKicad and Kosmo_panel directories.

If desired, copy the files from aoKicad and Kosmo_panel to wherever you prefer (your KiCad user library directory, for instance, if you have one). Then in KiCad, go into Edit Symbols and add symbol libraries

aoKicad/ao_symbols
Kosmo_panel/Kosmo

and go into Edit Footprints and add footprint libraries

aoKicad/ao_tht
Kosmo_panel/Kosmo_panel.