VCF

Voltage controlled filter that I built for my techno rack. It’s based on “Korg late MS20 filter” by René Schmitz.

René explains in the description how to add the high pass input. I didn’t manage to make it a switch, so there are two separate inputs for high pass and low pass 🤷‍♂️

Then I accidentally found out that if I remove one of the diodes in the original design, the resonance gets a crunchy color (which I find particularly nice for bass voices). So I implemented this function with a switch: Soft and hard resonance.

Specifications

Left and right view on the module:

Control board (bottom):

Main board (top and bottom):

Resources

Revision 2 (breadboard prototype)

• Schematic (PDF)
• Showcase and feedback on Instagram and Reddit

Revision 3 (two piece PCB)

• Video Demo
• Schematic (PDF)
• BOM (XLS)
• Panel Gerber files (ZIP)
• Control board Gerber files (ZIP)
• Main board Gerber files (ZIP)
• Showcase and feedback on Instagram
• Improvement potential on GitHub (issues)

Revision 4

What’s new? Optimized footprints, panel design and documentation.

• Build Document (PDF)
• BOM (XLS)
• Schematic (PDF)
• Improvement potential on GitHub (issues)