Mu-Tron Bi-Phase
Below are three incredibly cool graphics emailed from a fan of the site - thank you, Glenn! (Click each one...)
Mutron Bi-Phase with pedal, circa 1977. a/c powered. Two independent phase shifters housed in a large silver box with big knobs and switches and a wah-style foot pedal with 2 on/off buttons and speed control controlled by foot action. The worlds largest phase shifter! Settings include independent control over 2 phasors, 2 sweep generators with rate and shape (~ wave or square wave), manual or pedal option, Phasor A with depth and feedback plus gen 1 or pedal switch for sweep. Phasor B has more controls. Depth and feedback plus sweep sync option of norm or rev(erse) and sweep option of either gen1, gen2 or ped(al) and Phasor B input consisting of inA, outA or inB! Giant placards that fit over the housing include red marked settings for 3 effects examples: Stereo Phasing, Super Phasing and Two-Speed Phasing! This unit delivers the quintessential phasing sounds used in the 70's from the airplane-type whooshing sounds to the slow wide flanger-type effects. Adds fatness to clean sounds, great for ballad arpeggiating picking styles all the way to thickening an already distorted sound for added effect. Muted picking on power chords with gain to disco era octaves, this one delivers the goods. Plus, two-speed phasing yields some funkitized possibilities. Set one phasor slow and the other fast and the skies the limit. A favorite setting is the leslie cabinet sound from fast rate and moderate setting with little to no feedback. Then there's the classic setting of slower rate with much depth and feedback for reaching spatial territories! A quick way back to 1975 or ahead to 2050!

Sound: classic phase shifting and then some.
Looks: way cool oversized beast in blue and silver with funky footpedal
Pros/cons: all pro!
Desirability: big time rare factor and deluxe sounds make this effect all the rave
Over-all: killer! 
Bi-Phase MP3's:

Valley Arts, Marshall Model 6100, Gain

'64 Fender Strat, Marshall Model 6100, with Korg G4 Rotary Speaker Simulator:
'64 Fender Strat, Marshall Model 6100, with Korg G4 Rotary Speaker Simulator:
'67 Gibson ES-335, Marshall Model 6100, clean.
'67 Gibson ES-335, Marshall Model 6100, crunch.
'67 Gibson ES-335, Marshall Model 6100, crunch.