1977 MXR Phase 90

Model Description:

Witness a true legend. If there is one product for which the American company MXR Innovations is famous, it is this iconic but otherwise unassuming little orange block of an effect pedal, the fabled ‘script’ logo Phase 90. The 100% analogue 4‑stage Phase 90, designed by co‑founder Mike Barr in 1974, was the first pedal from the fledgling company. It was a remarkably successful debut for MXR. The early ‘script’ logo models have achieved hallowed status, principally for the exquisitely lush phase sounds. The Phase 90 is often used as a reference point for phaser pedals. Not long after launch, the Phase 90 had been joined by the subtler 2‑stage Phase 45 and the much more versatile 6‑stage Phase 100. The Phase 90’s reputation is all the more surprising given that the only knob governs the speed of the effect with no sign of a depth control. Perhaps the rule that ‘less is more’ applies to the Phase 90. Around 1976/1977, MXR introduced the 2nd generation pedals updating the design. The most visible difference was the change in aesthetics from the spidery script logo to a bolder block one. Importantly, it retained its electronic circuitry, so it sounded just like its predecessor. In the early 1980s, MXR changed the modulation circuit, so took the opportunity to add a factory power supply input and an LED to alert the user when it’s switched on. MXR ceased production in 1984 until Jim Dunlop revived it in 1987. Despite much effort, more recent reissues from the new owner are just not the same, even the Custom Shop models. Capturing the original magic means that the old pre‑Dunlop MXR pedals are much sought after on the vintage market with disproportionately high prices to match, particularly for the script logo versions of the iconic Phase 90.

Pedal Description:

This sturdy, diminutive and surprisingly heavy bright orange MXR Phase 90 (MX‑101) was made in Rochester, New York around the time of the change of image c.1976/1977. Both the enclosure and the baseplate carry the early script logo. The pot dates the pedal to mid‑1977 perhaps indicating it was one of the last script logo Phase 90s to leave the factory. I also had a 1977 Phase 90 with the MXR ‘block’ logo, so there was clearly some overlap between the designs. There are no signs of modification, other than a replacement battery clip, a very common occurrence. The enclosure’s condition is certainly not virgin but is very good for its age with a few superficial scuffs for its many years of use. It works perfectly and sounds great, just like it would have done when it was made. Simplicity really is the key here – it is almost impossible to get a bad tone from the oh‑so‑cool Phase 90 – just stamp on the footswitch, set the ‘speed’ control to suit and wallow in its characteristic warm, sensuous, sweet, swirling alchemy. Lovely. I’m generally not a massive fan of phase pedals, although this one can perhaps persuade me otherwise. If pushed, my personal preference is actually the Phase 90’s bigger brother, the Phase 100. Whatever your choice of orange phasers, there is plenty here to indulge your senses.


  • Made in Rochester, New York, U.S.A. in 1977
  • The ‘Speed’ knob controls the rate at which the phase effect cycles
  • Standard footswitch turns the effect on and off
  • Standard ¼” input and output mono jack sockets
  • 1st generation ‘script’ logo enclosure and baseplate
  • No LED or DC power supply input
  • No box or instruction manual

Detail Gallery:

 ← Return to ‘effects’ page

Like it? Why not share it?