Uni-Vibe

The Uni-Vibe, also marketed as the Jax Vibra-Chorus,[1] is a footpedal-operated phaser or phase shifter for creating chorus and vibrato simulations for electric organ or guitar.

Designed by audio engineer Fumio Mieda,[2] it was introduced in the 1960s by Japanese company Shin-ei (at the time Honey) originally branded as the Vibra-Chorus.

The effect (now named Uni-Vibe) was modified to have easier access to its fuse, and a speed control foot pedal was added.

The effect has made its mark on tracks like Robin Trower's "Bridge of Sighs", Jimi Hendrix's "Machine Gun" and Pink Floyd's "Breathe".

[3] The effect, though often associated with chorus, is in fact created through a staggered series of phasing filters and an optical circuit utilizing LDRs (Light Dependent Resistor) and an incandescent bulb inside a light shield with a reflective interior, unlike the usually aligned filters of a normal phasing effect.