Based on the Roland System 700 state variable filter module. Lowpass, bandpass and highpass outputs.
A big part of the sound of the State 700 is the way in which resonance is reduced as the audio inputs are driven harder. It won’t self oscillate with a hot audio input, throttle back a little and you’ll get squelchy ear bleeding resonances!
soundcloud demo is here: state 700 vcf
full kit includes everything you need to build the module, all parts individually bagged and labelled