Demo 2: VCO/VCF/VCA

A purely analog setup: Voltage-Controlled Oscillator, Filter, and Amplifier, along with a pair of paddle-operated CV sources, all mounted to a QICBase_ERL, which is a 34-HP Eurorack base, which gets its power from the rack.

Depressing a paddle moves a magnet (glued to the bottom of the paddle) closer to a Hall effect sensor (sticking through the hole) which changes the output voltage.  Those control voltages go to a pair of attenuverters (above the paddles), allowing you to control gain, polarity, and offset, before feeding the VCO/VCF/VCA inputs.

The VCO/VCA/VCF are slightly redesigned versions of Cabintech CEfx modules:

https://cabintechglobal.com/cefx

I stretched the boards a bit and added connectors to make them QICboard-compatible.

For this demo, I made the following "normals": the yellow hookup wires visible on the bottom pic:

QICMagSensor M1 (amplified sensor out) normalled to leftmost QICAttenuverter normal in.

QICMagSensor M2 (amplified sensor out) normalled to rightmost QICAttenuverter normal in.

VCO pulse output normalled to VCF input.

VCF resonance pot wired to resonance CV input.

VCF output normalled to VCA input 1.

Check out the CEfxI and QICMagSensor pages for schematics.