Available as an assembled Module and as a DIY project.
This Module is currently available.
Percussion Aid
Perk is a percussion aid. This solution for drums is to take any input waveform, apply a filter and an envelope, then a VCA to complete the voice.
The envelope goes to the filter by way of an attenuating knob, for varied tonal depth. CV over envelope length and filter; a BYO envelope jack (labeled level) can be held open to function as a direct filter and overdrive.
Internal noise source is exposed at the bottom center, and is normalled to the input so you can use it as a snare with no input waveform. Resonance and filter cutoff can shape the tone into windy basses.
Given various input shapes and levels it can make many fun percussion sounds. Perk contains a decay-only triggered envelope with voltage control, exposed as a utility output bottom left and has a wide range of times. Alternate input for 'level' allows external envelopes. The envelope also triggers the filter for that resonant kick you need.
The SSI2164 chip Application Note 701 shows several ways to make a resonant lowpass filter, we've modified that to allow eurorack IO and a final fourth stage VCA to control the post-filter level. It's a really modular take on performable percussion voices.
Easily turn any osc into a full voice with this filter/env/amp combo module in 8HP. Originally planned with the XORBell module as rough metallic tones under a resonant lowpass make for luscious resonantor voices.
