Plenty of effects pedals need a row of knobs to feel complete. The MXR Phase 90 needs one. Twist Rate and the orange box moves from a slow spatial shimmer to a fast, swirling swoosh that has defined phaser for more than four decades.
Here is what the Phase 90 is, why it stuck, which versions to consider and where to buy one.
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What it is
The MXR Phase 90 is a phaser pedal: it splits the guitar signal, shifts the phase of one path and blends the paths back together so moving notches sweep through the tone. Dunlop's product page describes the range as running from subtle, spatial shimmer to high-velocity swooshing with a single Rate control.
The standard M101 lives in the familiar small orange enclosure. It runs on a nine-volt battery or a nine-volt adapter, including Dunlop's own power supplies. There is no mix knob and no stages switch on the basic model. The point is the sound you get when the circuit is left alone.
Where it came from
Dunlop, which owns and builds the MXR line, says the Phase 90 has been a mainstay on pedalboards for more than four decades and became the icon of its effect category. Legendary riffs across genres have used that lush, watery movement, which is why the little orange box still shows up on boards next to newer, denser modulation pedals.
MXR itself dates to the 1970s boom in compact American stompboxes. The Phase 90's job in that era was to put studio-style phasing under a footswitch without a rack. The circuit stayed famous enough that Dunlop still sells not only the standard model but Script logo and 1974 Vintage recreations for players who want specific eras of the sound.
Why it is still worth buying
- One knob is a feature. Rate is enough. You spend time playing instead of menu-diving.
- The voice is the reference. When people say a pedal sounds like a Phase 90, they mean this exact swirl.
- It is small. The compact footprint leaves room for drive, delay and tuner on a crowded board.
- It works beyond guitar. Dunlop notes the pedal has been used across instruments and styles; bass and keys players lean on it too.
- Versions cover eras. Standard, Script and 74 Vintage let you pick modern reliability or older voicing.
Which version to buy
- Standard Phase 90 (M101). The current orange classic. Start here unless you already know you want a vintage voicing.
- Script Phase 90. A Script-logo version with light-emitting diode (LED) indication for players who want the early look and a specific take on the circuit.
- 74 Vintage Phase 90. Dunlop's recreation aimed at the mid-1970s flavor of the pedal for purists chasing that era.
If your board already has a busy modulation section, the standard M101 is still the clearest way to hear what every other phaser is comparing itself to. If you collect MXR history, Script or 74 Vintage are the deeper cuts.
How it fits a board
Phaser usually sits after drive so the sweep moves across an already saturated tone, though some players put it before for a milder effect. Either way, the Phase 90 pairs well with other compact classics covered on the site, from the Boss DS-1 Distortion to the Electro-Harmonix Big Muff Pi and the EarthQuaker Devices Plumes.
For a fuller starter kit around the pedal, see our home studio starter gear guide. More recording and pedal coverage lives in the home studio hub.
Power is simple but worth planning. The Phase 90 accepts a nine-volt battery or a standard nine-volt center-negative adapter. On a board with several MXR pedals, a shared Dunlop brick keeps cable clutter down. Bypass the pedal when you want a dry rhythm tone, then kick it on for chorus-like movement in a lead or for a slow swirl under clean chords.
Where to buy
Dunlop sells the Phase 90 through the official MXR product page and its dealer network. You can also pick up the MXR Phase 90, the MXR Script Phase 90 with LED or the MXR 74 Vintage Phase 90. Check whether you need a separate nine-volt supply; many listings are pedal only.
For more compact effects with history, keep browsing the music and gear posts above. More in our home studio hub.
