Dual 2-pole LP/HP filter with parallel and serial routing

The 3350 VCF contains two independent voltage-controlled 2-pole filters. Each can be switched between low-pass and high-pass, with its own cutoff offset and resonance control.

In parallel, the filters can process one source as a stereo pair or two separate sources. In serial, filter A feeds filter B for an approximately 4-pole low-pass or high-pass response, or a band-pass patch when the responses are mixed. The shared Frequency control moves both cutoffs together; Separation moves them in opposite directions for stereo spread and animated contrasts.

F CV modulates both cutoffs together and is not calibrated for 1 V/oct tracking. S CV modulates their separation. At high resonance, the filters can approach self-oscillation. AB out carries filter B or the final serial output; it is not an A+B mix.

Currently available as a DIY kit only.

Manual and build guide: https://docs.google.com/document/d/1Yekch6zRRpSooxRThgtS0uay2OZBftZSPzv6qGX__jw/edit

https://www.etsy.com/listing/4587113258/eurorack-diy-3350-vcf-full-kit-dual-2