The PRC3 packs a compact but powerful punch as the BugModular's first resonant filter. It is a State Variable design offering Low/Band/High/Notch outputs with voltage-controlled Cutoff (Freq) and Resonance (Q). The design has been updated to Rev.2 version, but with no changes other than in construction.
State Variable (12db/oct) filters are quite a common sonic building block and can be found on such synths as the famous SEM. Typically they offer three separate outputs - Low/Band/High-pass - but an extra Notch (band-reject) output can easily be added by combining the Low & High-pass outputs. Resonance can be dialed from low to extreme, but the filter will not self-oscillate.
The filter features as 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.
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. Instruction Sheet (pdf)
Typical bipolar +/-5V DC-coupledWidth:
+ve 20mA / -ve 20mAUser Adjustments:
Added on Wednesday 08 April, 2009.