Wiard/Malekko boogie filter
The Boogie filter (Modcan A format) is vactrol based and features a resonant low pass, one audio input, two cv inputs (one key in and one with attenuator) and outputs for 6dB, 12dB, 18dB and 24dB as well as a mix of all four. There are two user-friendly jumpers on the back of the module that control the phase of the 12 and 24dB outputs.