Rastop Envelope Filter


  • Gain
    Matches the by-passed volume of guitar with Filter. Avoid distortion with humbuckers at high settings (some like it though).
  • Mix
    A new feature- adds clean, signal to the path, very nice sparkle for rhythm playing, at maximum creates subtle effect of phasing (slight pitch modulation) as a result of summing inverted filter signal with non-inverted clean signal.
  • Sensitivity
    Simultaneously adjusts the sweep range, attack and decay time.
    Low settings: low sensitivity, slower attack and faster decay.
    High settings: wider sweep range, faster attack and slower decay. Adjust it for your guitar pickups output and effect depth.
  • Mode Switch
    LOW position: full range
    HIGH position: less bass, adds sweep-dependent volume change. Very sensitive to Sensitivity knob.
  • Resonance Frequency Switch
    LOW and HIGH accordingly to the position.



  • Start with Gain and Sensitivity in the middle, Mix- all way down.
  • Some technical details: Optical, LDR-based VCF, full-wave rectifier and hi-gain NPN transistor LED drive for minimum distortion. High input/low output impedance. True By-Pass switching.
  • Exterior/paint job available: Tweed, Black Tolex, Blue Hammered paint.
  • Custom options:
    • custom exterior with customer-provided materials
    • Two 9V batteries version for extra clean headroom when using super-hot humbucking pickups
    • LED color of choice
    • for bass guitar: combined with MOSFET distortion and voiced for thunderous lows.
  • Most recent forum threads

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