Effectsdatabase: The MXR M-120 Envelope Filter is an analog tone modifier that produces automatic "wa-wa" effects through a voltage-controlled low-pass filter circuit. The filter's upper cutoff frequency is governed by the amplitude of the input signal, so higher input levels raise the cutoff frequency. This relationship causes the signal's loudness to directly influence the perceived brightness of the sound, creating a dynamic, touch-responsive filtering effect that follows the player's articulation.

The circuit provides two primary controls that shape the filter response. The Threshold control adjusts the sensitivity of the filtering action relative to the input signal level, determining how strongly the effect responds and how bright the resulting tone becomes. Lower sensitivity settings yield more subdued filtering suitable for accompaniment, while higher sensitivity produces a more pronounced effect for lead playing. The Attack control sets the time required for the filter's cutoff frequency to reach its peak after a note is played. At maximum clockwise position, the response is nearly instantaneous, while longer attack times introduce a delayed sweep that emphasizes a "wa" character at the onset of each note.

The pedal is compatible with a range of electric instruments, including guitar, bass, piano, and clavinet, and is intended to add dynamic variation and expressive filtering to both solo and accompaniment contexts.

It's a vintage pedal, but it is still in gorgeous condition. Not a very common circuit either!

Optically 9/10. Its fully functional!

All the other pedals in the last picture are also for sale! Send me a message if you are interested in any of them. Check the Guitar Space store page for more interesting gear and deals!

!TO ALL AMERICAN BUYERS: CONTACT ME BEFORE PURCHASE TO SORT THE TARIFF THING OUT!