Uni-Vibe

The Uni-Vibe is a modulation pedal introduced in 1968 by Japan's Shin-Ei corporation, designed by Fumio Mieda as a pedal alternative to a rotating Leslie speaker¹. It produces a rich, three-dimensional swirling, pulsing effect, with a harsher drop-off in the waveform that gives it a throbbing sound unlike a phaser's smooth sine wave²³⁴. Technically it is a four-stage phaser, but its optical circuitry, a pulsating lightbulb surrounded by light-dependent resistors and sensors, gives it a unique sonic signature, and it uses discrete components rather than op-amps⁵⁶⁷. Its speed control is tied to a foot pedal, allowing more dramatic speed changes than a Leslie's mechanical fast and slow settings⁷. Used by Jimi Hendrix, Robin Trower, and David Gilmour, it has appeared on countless classic recordings⁸⁴.