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Used Electro-Harmonix Q-Tron Envelope Filter


In good condition for being an older pedal. Has been tested and works great. The filter on this pedal is like no other! You can really dial in some sweet and funky tones with it. Comes with power supply.

Original EHX Description :

Mike Matthews, founder of Electro-Harmonix, and Mike Biegel, designer of the Mutron III, have together created the first all-new Electro-Harmonix product in 15 years: The Q-Tron envelope controlled filter. This new effect uses the same opto-electronic design of the Mutron-III and has an increased frequency response and an improved signal-to-noise ratio. Has all Mutron-III features plus switchable Boost and Filter Mix mode.


There are seven onboard controls :

  1. Drive Switch (up/down) - selects direction of filter sweep : up (wah) or down (ow).
  2. Range Switch (Hi/Low) - Emphasizes vowel like sounds in low position, overtones in high position.
  3. Gain Control (0-11) - Functions as both a volume control and a filter sensitivity control in boost mode. In normal mode it acts only as a filter sensitivity control, unlike the Mutron-III which also changes the unit's output volume.
  4. Boost Switch (Normal/Boost modes) - Normal mode allows setting the Gain control without changing the output volume.
  5. Peak Control (0-11) - Determines frequency peak of filter. Makes more "effected sound" when turned up more.
  6. Mode switch (LP, BP, HP, MIX) - Select the frequency range for the filter to sweep. Low Pass is lows, Band Pass is midrange, High Pass is treble. MIX mode (new feature not on the Mutron-III) combines BP with dry unprocessed sound.
  7. Bypass switch (in/out) - Turns effect on and off.



  • Includes 24 volt AC adaptor (will not run on batteries).
  • Comes in strong multi-ply wooden box
  • POWER indicator LED
  • 2 outputs - normal and effected outputs.
  • True bypass DPDT switching.

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