Korg Monotron Mods and Resources

Published 2011

Korg Monotron (Front)

Despite its simple design, the Korg Monotron is a surprising versatile synthesizer. This page documents the mods I have made to my Monotron and resources for other Monotron owners.

Two invaluable pieces of documentation for modding are the official schematic and this annotated photo labeling each component on the Monotron's PCB.

MIDI Control

Serial CV Interface - Installed

I built a device to control the Monotron with a computer; details here. Although it works, the Monotron's extremely limited range and annoying filter click made it almost useless for making music.

Filter Keyboard Tracking Fix

Korg Monotron Filter Tracking Mod

The filter on my Monotron didn't track the keyboard/ribbon properly; it opened up too much on higher notes, causing a difference in timbre. To fix it, I removed R42, which controls how much the voltage from the ribbon affects the filter cutoff CV, and replaced it with a 1MΩ 20-turn trimmer potentiometer. The trimmer was adjusted to give good tracking over the whole keyboard range.

Patch Sheet

Korg Monotron Patch Sheet

Analog synths used to come with patch sheets to record patches for later recall. I made one for the monotron, which can be found here (png version).