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  • Various portamento effect. Encore MIDI-to-CV driving VCO>>VCF>>VCA chain [1.4 Meg]
  • Warping an audio square wave. The lag is a 6dB/oct lowpass, after all! [1.4 Meg]

  • MOTM-820 Voltage-Controlled Lag Processor
    $309 assembled & tested

    The MOTM-820 is used to add slew to an input. The most common use would be to add portamento to a control voltage feeding a VCO (hopefully, a MOTM-300 VCO). In analog keyboards with portamento (Moog called this glide) the rise and fall times were the same. This is because a simple RC filter is controlled by a single pot. The shape is the same: an exponential rise and fall. Although we are used to hearing this shape, the fact that we have an exponential voltage feeding an exponential response (1V/Oct of the VCO) means that musically we are limited.

    The MOTM-820 is your solution! It is the most advanced lag processor ever designed. How can we claim this? Well, just check out the features:

    • Independent voltage control of both rise (UP) and fall (DOWN) times
    • Times variable from 500us to 5 minutes
    • Ganged UP/DOWN control to emulate standard portamento effects
    • A new SHAPE control that varies the glide slopes from Linear to Log
    • Remote or panel BYPASS to turn the effect off without any DC shift!

    Easy to build, the MOTM-820 also offers a "hidden multiple": it can drive 3 VCOs (or other modules) from a single input! The output stage is a special "capacitive cable driver" for driving long cables (up to 20 feet) without any voltage drop!