The Befaco BF-22 DIY Kit contains the parts to build Befaco's BF-22 VCF, a dual high-pass/low-pass Eurorack filter based on the Sallen-Key circuit of the early Korg MS-20. It is aimed at modular users who want that dirty, screaming early MS-20 character in their rack and who are comfortable with a medium-difficulty solder build.
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Two filter channels modelled on the early MS-20 Sallen-Key design, each switchable between high-pass and low-pass
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Two CV inputs per channel, with an attenuverter on the first
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Voltage-controlled resonance, with attenuverters on both cutoff and resonance; Befaco gives the resonance a little more presence than the original
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Link switch that routes the output of channel one into the input of channel two
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Cutoff CV tracking over 3 octaves
A classic way to use it is to set the first channel to high-pass and the second to low-pass, then engage Link to run them in series for the familiar MS-20 band-shaping and squeal. Run separately, the two channels can process two different signals.
Befaco is clear that the BF-22 also carries over the MS-20's noise floor, so it suits gritty, characterful patches rather than situations where a very quiet filter is needed. The kit includes everything needed for a finished module, including a power cable and four Befaco Knurlies M3 rack screws. Befaco publishes an assembly manual, user manual, schematic, BOM and an interactive build guide to support the build.