PRC3A – SV Filter
The PRC3A is a 12db/oct State Variable Filter offering Low/Band/High/Notch Outputs with voltage
controlled Cutoff (Freq) and Resonance (Q).
The filter features a single audio input and two output sockets - one is switchable between Low & Band-
pass while the other goes between High-pass & Notch.
Cutoff Frequency is set by a main dial plus two external CV inputs - one CV input is full range 1V/Oct
while the other has a depth control. Resonance also has main dial plus CV modulation with depth
control. Note that such filters do not offer self-oscillation resonance, but interesting areas can be
achieved through patching – check
otoskope's Sine to Chaos
thread for further details -
http://www.muffwiggler.com/forum/viewtopic.php?t=51588
You can 'Ping' the filter by applying a sub-audio signal with abrupt edges (eg. pulse wave) to the input -
turn the resonance up to full and adjust the frequency to adjust the pitch of the ringing. To take this even
further, try FM'ing the Cutoff with an audio-rate signal.
Note – the 1V/Oct response is only rough – there is no trimmer for fine tuning.
