The Doctor Q from Electro-Harmonix is a compact envelope filter pedal that generates percussive filter sweeps and dynamic picking responses that produce Wah-like tones. The Doctor Q pedal features a simple one-knob range control, true bypass, and switch-selectable bass boost.
The Doctor Q pedal was first manufactured 1976-1983, later reissued in 2001. Funky envelope filter with control for sweep range and a switch to select between bass/guitar voicing.
The Gear Rack