The Electro-Harmonix Doctor Q Envelope Filter is a classic vintage pedal for authentic ’70s funk sounds. Originally introduced in 1976, the Doctor Q works equally well with guitar and bass, delivering its unmistakable, quacky envelope-filter character.

A convenient selector switch allows you to choose between guitar and bass voicings. Operation is refreshingly simple: a single Sweep Range control lets you adjust the intensity and tonal character of the filter.

A straightforward vintage effects pedal with unmistakable retro character — ideal for classic funk, soul, and psychedelic sounds.

• Potentiometer date code: 1977
• Made in the USA

Condition: Used / Good

Before resale, all used pedals are:
✓ Carefully inspected and tested
✓ Thoroughly cleaned