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