INTRODUCTION The BF-22 VCF is a dual Hi/Low-pass filter inspired by the Sallen-Key filter from the early MS-20. FEATURES The module features attenuverters (inverter-attenuators) as an addition to the normal CV control for Cut-off and Resonance, and offers a little more presence in the Resonance than the original. The CV control for Cut-off keeps tracking through 3 octaves. The Link switch connects the input of the second unit into the output of the first.