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Shin-ei Uni-Vibe (c.1968)
once owned by Jimi Hendrix
(exhibited at Experience Music Project)

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, and then released in North America by Univox in 1968.[1]

It was intended to emulate the "Doppler sound" of a Leslie speaker. Though not very successful as a Leslie simulator, the Uni-Vibe became an effect in its own right, putting its stamp on tracks like Robin Trower's "Bridge of Sighs", Jimi Hendrix's "Machine Gun" and Pink Floyd's "Breathe".


The effect, though often associated with chorus, is in fact created through a staggered series of phasing filters and an optical circuit called LDR, unlike the usually aligned filters of a normal phasing effect. Unlike most other phaser pedals, this is achieved without the use of op-amps.

The Uni-Vibe phase shifter was known for its throbbing, hypnotic pulse and lo-fi sweep. These unique effects set it apart from other modulation-type effects at the time.[1]

rack mount modified Uni-Vibe (right mid) on David Gilmour's effects rack.
(exhibited at Expo Pink Floyd)

The Shin-ei Uni-Vibe was also sold as a Univox product.

As of 2020, "Uni-Vibe" is a registered trademark of Dunlop Manufacturing, Inc.[3]

Notable users of the Uni-Vibe have included Jimi Hendrix, Robin Trower, Trey Anastasio and David Gilmour of Pink Floyd.[4]


  1. ^ a b c Harry Shapiro, Michael Heatley, Roger Mayer, Jimi Hendrix Gear, page 120, Voyageur Press
  2. ^ Molenda, Mike; Pau, Les (2007). The Guitar Player Book: 40 Years of Interviews, Gear, and Lessons from the World's Most Celebrated Guitar Magazine. Hal Leonard. p. 222.
  3. ^ "Trademarks". Dunlop Manufacturing, Inc. 2020. Archived from the original on 2020-08-30. Retrieved 2020-08-30.
  4. ^ Tolinski, Brad. "Welcome to the Machines". Guitar World (September 1994).

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