The FM Drum is a percussion module designed to make far-out and strange sounds. It features a manually controlled modulating oscillator and a voltage controlled oscillator. Each oscillator has both square and triangle waveshapes, selectable with toggle switches. It also accepts external CV for modulation. It is easy to patch, just input a trigger or gate source and out comes a new sound.

This PCB is available with footprints for DIP or SMD versions of the LM13700. All other components are through hole, the 13700 is the only part becoming harder to find at an affordable price through hole.  

Demos, build documentation, drill guide, are available here.

Unfinished panels are drilled by hand in my garage, they are bare aluminum that may be scratched.  They are intended to be painted, etched or otherwise finished later.

Pre-Assembled Modules are built after the order comes in.  Build time can be a few days or a few weeks depending on what parts I have on hand.  When ordering, please leave a comment at checkout if you have preferences on what color(s) the panel is painted.