Diode Ladder VCF (8HP)

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.