Originally designed by Fumio Mieda in the 1960s, the Uni-Vibe was intended to replicate the doppler effect created by a rotating speaker (like a Leslie). A four-stage phaser circuit powered by four photo-cells and a rotating bulb, the design was considered to be a failure in its original Leslie-emulating purpose. Yet the device’s swirling, undulated pulses lead it to catch on as a unique and expressive effect in its own right, and was quickly adopted by many of classic rock’s great guitarists, with Jimi Hendrix and David Gilmour being two of the pedal’s most notable users.
For many years, Trey used a 1990s recreation of the original Uni-Vibe called the Black Cat Vibe. The Black Cat was a rack unit designed by Fred Bonte for Bob Bradshaw at Custom Audio Electronics (CAE), which offered them to customers as the CAE Black Cat Vibe. Presumably when Trey went to Bradshaw for his RS-10 midi-controller setup, Bradshaw set him up with a Vibe as well. Trey also used Bradshaw’s CAE Tremolo for many years.
At the 2014 Dick’s show, Trey had both the Black Cat Vibe and, for the first time, an original Vintage Shin-Ei Univibe in his rig at the same time. In all likelihood, Trey was A/B’ing them during these shows to see if the Shin-Ei was as good as its reputation, and he must’ve liked it, because the Black Cat hasn’t appeared on the rig since and Trey has begun to use the Shin-Ei prolifically. Here’s an example of how it sounds with Phish from Summer 2017:
Here’s a shot of the Shin-Ei in place:
Trey's Guitar Rig 