Serge Variable Q VCF

VCFQFront 

From the Serge Catalog:

The VARIABLE Q VCF (VCFQ) is an excellent general-purpose VCF offering simultaneous low-pass, high-pass, band-pass and notch (band-reject) outputs. The resonance (Q) of this filter is dynamically variable by manual or voltage control. The VCFQ has two signal inputs. One incorporates an automatic gain control to prevent the filter from overloading at high Q settings. The second input has a level control so that the percussive effects of overloading the filter can be exploited. When a pulse is applied to the Trigger input, the filter will ring, producing a damped waveform similar to that produced by striking a resonant object.

My Serge VCFQ was bought as a semi-kit from SMMS (Serge Modular Music Systems) in the early 1980's

This module can be built as DIY with a PCB from CGS. All CGS Serge modules are authorized by Serge Tcherepnin.

Info on the CGS module is HERE