Diode Ladder VCF (8HP)
Due to the compliance requirements of the European Union GPSR (General Product Safety) Regulations I am currently unable to ship to the following destinations: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland (including Northern Ireland), Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain and Sweden. In addition, I am unable to ship to Norway, Iceland or Liechtenstein.
Think of this as the bigger, uglier sibling of the MS20-style YAMS filter - it's bigger, badder, squallier and has voltage-controlled resonance too.
It's built around the really rather splendid LM13700 operational transconductance amplifier. There are also a lot of diodes (14 of them, to be precise).
Eagle-eyed viewers will notice a pair of trimmers on the back of the board - these control the cutoff offset (response when cutoff pots are fully CCW) and the V/oct response for the cutoff frequency. Out of the box you may need to tweak these until you get a response you like.
Works best with square or saw-based waveforms.
Note that this module ships with an old-style purple/gold panel - once these modules are gone, they're gone.