PCBs and FR4 front panel (only) for a multimode voltage controlled filter synth module. This module is in LMNC's Kosmo format (20 cm high) and is 10 cm wide.

The circuit is based on a partial design by Electric Druid. It uses pole mixing to provide eight different filter responses: Two types each of low pass, high pass, band pass, and notch filters, selectable via a rotary switch. If that isn't enough, an expansion header on the PCB allows connection to a daughterboard or an expansion module that can provide additional filter responses or other functionality. (A daughterboard design is available, but has not been tested; as for expansion modules, I look forward to seeing what you come up with!) Cutoff frequency and resonance both are voltage controlled.

The user needs to source parts and assemble them. (Photo of my own assembled module for illustrative purposes only.) Easy through-hole construction.

Be sure to see the Github repository (linked below) for BOM, schematic, and other information.