by Phil Taylor
The original Uni-Vibe was originally developed as a compact, portable Leslie rotating speaker system simulator. Although it did not accurately reproduce the sound of the Leslie, artists such as Stevie-Ray, Robin Trower and Jimi Hendrix, used it as an effect in it’s own right thus the Uni-Vibe became firmly entrenched in rock ‘n’ roll history.
The vibe is essentially a phaser where the four phase-shifter sections are tuned to produce two notches in the low and high end of the frequency spectrum. A low frequency oscillator (LFO) sweeps these notches up and down the spectrum to create the vibe effect. The position of the vibe in your signal chain is therefore critical, as removal of frequency content in this way drastically alters the tone of any other effects that precede the vibe.
Up until a couple of years ago my preference had always been to connect vibe post any gain effects (overdrive, distortion, fuzz or preamp). The technical reasoning behind this was that there is more frequency content to for the vibe to work on and and therefore the effect sounded more intense. Vibe can be catagorized as a modulation effect (phaser, flanger and chorus) and I was following the well known mantra.
Guitar -> Compression -> Gain Fx -> Equalisation -> Modulation Fx -> Delay -> Reverb -> Amplification
Where modulation effects follow gain effects. However, because the vibe introduces severe filtering, it completely disrupts any fine adjustments to tone shaping made with a graphic, parametric eq. or even just the basic tone controls on your favorite overdrive pedal. A good overdrive/distortion sound depends heavily on tone shaping, so putting a vibe after it completely ruins time and effort painstakingly spent dialling up your prized signature overdrive tone.
There are many players out there who run their vibes before overdrive/distortion and one my customers advised me try this . . . Now I’m sold on that configuration. However I still keep phasers/flangers further down the chain – after-all, if you want to achieve Alex Lifeson’s massive swirling guitar sound for the intro to “Spirit of Radio” phasing must follow distortion! Many players reading this will probably be interested in replicating Jimi Hendrix or Robin Trower’s sound, so how does this stack-up in the light of what’s just been discussed.
Well, Hendrix applied his Uni-Vox Uni-Vibe towards the end of the effects chain, adhering to how a real Leslie rotating speaker would be used. His chain went:
Hendrix’s cranked Marshall Plexis provided further tone-shaping (crunch!) after the Uni-Vibe when he rolled his guitar volume knob up (as he would have done for, say “Star Spangled Banner” at Woodstock or “Machine Gun” later on. While Jimi’s Fuzzface was being modulated by the ‘Vibe rather than the ‘Vibe being fuzzed by the Fuzzface (which by this time had for a couple of years been usually modified by Roger Mayer, as typified by his Axis Fuzz, usually housed in a Fuzzface casing, as Mayer has detailed in various interviews that can be found online), his lead “drive” tone was not just Fuzz, but a Fuzz -> cranked EL-34 power amp valve combination. Note too that while Mayer recommends his Octavia after the Fuzz, the photographic & film evidence of the Fillmore East Band of Gypsies gigs shows a chain of Strat -> Vox wah (Mayer-modded) -> Mayer Octavia -> Fuzzface (guts replaced with Mayer Axis Fuzz circuit) -> Uni-Vibe -> three cranked Marshall Plexis.
That said, vibe doesn’t really sound at it’s best in this position and, to my ear, is more defined and clearer at the front. That’s how Robin Trower uses it, placing his vibe towards the beginning of his effects chain and I can confirm that “Bridge Of Sighs” or “Day of the Eagle” sound best in this configuration. The conclusion I draw from this is, there are no firm rules, go ahead be progressive and experiment, after all that’s what all great guitar players do, isn’t it?.