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?.
