MS-20 VOLTAGE-CONTROLLED FILTER
The MOTM-420 is a switch-selectable LP/NF/HP (lowpass/notch/highpass) voltage-controlled filter. Using the same filter structure as the Korg MS-20, the MOTM-420 has a unique "cutting" sound that is perfect for techno, acid, house, and other dance music. The VCF will overdrive/distort in all modes, and the resonance can be cranked into self-oscillation. The LP/HP slopes are -12dB/oct and the NF is -6dB/oct.
The MOTM-420 includes an on-board 3-channel mixer that can accept audio signals or control voltages. This eliminates the need for a separate mixer module in most patches. Multiple MOTM-420s can be chained in series to exactly emulate the MS-20 filter (HP filter followed by LP filter).
Unlike the more common 4-pole LP filters, the MOTM-420 has a brighter and more "glassy" sound. This is due to the selection of parts used, in addition to the filter design. The VCF will alter its resonance as the input amplitude varies. This was a "flaw" in the original filter design, but is the main reason for its amazing sound!
The MOTM-420 has three separate inputs, which can accept line-level audio signals from synths, drum machines, or samplers. By using a "direct box," you can also run a guitar or bass through the filter. Use a voltage-out pedal for sweeps as you play.