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By Andrew Sanchez, Larry Hendy, Charles Stella and Mike Marsh

  • Extreme FW sweeps with EG and LFO [650K]
  • 2 different riffs, with LP-Notch-HP filtering in sequence [769K]
  • Prog rock riff with saw waves and moderate resonance [188K]
  • Simple riff with ever-increasing resonance settings [496K]
  • Notch mode with very high resonance creates vocal formants [280K]
  • Female vocal track filtered with LP, manual knob-twiddling [107K]
  • Notch mode demo showing 'spongy' phase-sound. [321K]

  • MOTM-420 Voltage-Controlled Filter
    $339 assembled & tested

    The MOTM-420 is a switch-selectable LP/NF/HP (lowpass/notch/highpass) voltage-controlled filter. Using the same filter structure as the MS-20, the MOTM-420 has a unique "cutting" sound that is perfect for techno, acid, house, and other dance music. The VCF will over-drive/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 2 on-board 3-channel mixers: one for audio and one for control voltages. This eliminates the need for a separate mixer module in most patches. Multiple MOTM-420's can be chained in series to exactly emulate the MS-20 filter (a HP followed by a LP).

    Unlike the more common 4-pole LP filters, the MOTM-420 has a brighter, "glassy" sound. This is due to the selection of parts used, and the filter design. The VCF will alter it's resonance as the input amplitude varies. This was a "flaw" in the original design, but is the main reason for the sound!

    The MOTM-420 has 3 separate audio inputs, that can take audio signals from any other synth, drum machine or sampler. By using a "direct box", you can run a guitar or bass through it. Use a voltage-out pedal for sweeps as you play.

    Only average in difficulty, the MOTM-420 is a unique module that can be finished in 1 day's time.