UBZR1 Voltage Controlled Filter
The VCF is a 24 dB/octave low pass filter.
My design has
- OpAmps instead of discrete transistor output amp.
- Voltage controlled resonance level by using a LED controlled photo transistor
Schematics as PDF or JPG
The VCF design follows a design published 1978 in German periodical "Funkschau". This in turn was based on the classical Moog transistor filter ladder.