Manhattan Analog SVVCF
State-variable voltage-controlled filter
The Discrete SVVCF started out as the SVF design (based on the Jurgen Haible discrete 2040 gain cell) which Scott Stites posted over at electro-music.com years ago. After removing the original audio input section and grafting on the CP3 mixer circuit (more transistors!), the result is a very thick-sounding filter whose character varies depending on how hard you drive the inputs.