voice of saturn voltage controlled filter
The Voice of Saturn Filter unit has a joystick or Voltage Controlled low-pass filter based around a CEM 3372 IC. It accepts two inputs that have independent VCA's as well as a final output VCA. Both cutoff and resonance are voltage controllable. The joystick is modular, and can be patched to control or attenuate other signals.
The VoS Sequencer comes in several different kit forms as well as manufactured units and is open source. Schematics and more information can be found on the Curious Inventor website.
Voice of Saturn Voltage Controlled Filter (Frac Format) from Travis Thatcher on Vimeo.