The MXR Phase 90 is a phaser

effects pedal An effects unit or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing. Common effects include distortion/overdrive, often used with electric guitar in ele ...

introduced in 1972 by MXR.

History

The Phase 90 was the first pedal sold by MXR and helped launch the company in 1974. The original model had a simple orange enclosure with a script style MXR logo. In 1977 MXR changed its logo to a block style. There was a transitional period in which some Phase 90s with script logos had box logo circuits, and vice versa. Production ceased when MXR went bankrupt in 1984. When

Jim Dunlop Dunlop Manufacturing, Inc. is a manufacturer of musical accessories, especially effects units, based in Benicia, California, United States. Founded in 1965 by Jim Dunlop Sr., the company grew from a small home operation to a large manufacturer o ...

bought the MXR brand, production resumed. The Dunlop models have an LED to indicate the effect is engaged, and an optional AC power supply. There are several styles, including the standard block logo version, a reproduction of the script logo version, and an

Eddie Van Halen Edward Lodewijk Van Halen ( , ; January 26, 1955 – October 6, 2020) was an American musician and songwriter. He was the guitarist, keyboardist, backing vocalist, and primary songwriter of the rock band Van Halen, which he co-founded along ...

signature model. Van Halen first heard

Robin Trower Robin Leonard Trower (born 9 March 1945) is an English rock guitarist who achieved success with Procol Harum throughout 1967–1971, and then again as the bandleader of his own power trio known as the Robin Trower Band. Biography Robin Trowe ...

use the pedal in the mid-1970s, and used it on songs such as "

Eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...

", "

Atomic Punk ''Atomic Punk'', released in Japan as and in Europe as ''Dynablaster'', is a video game released for the Game Boy in 1990 by Hudson Soft, as part of the ''Bomberman'' series. It was the first game of the series to be released on the Game Boy ...

", "

Ain't Talkin' 'bout Love "Ain't Talkin' 'bout Love" is a song by American rock band Van Halen. It was released in October 1978 as the third single from their 1978 debut album, ''Van Halen''. This song is one of the few David Lee Roth-era songs that subsequent replaceme ...

", " Everybody Wants Some!!", and " Drop Dead Legs". The 1974 Hand Wired Phase 90 is a recreation of an original 1974 pedal using

new old stock New old stock (NOS), or old stock for short, refers to aged stock of merchandise that was never sold to a customer and still new in original packaging. Such merchandise may not be manufactured anymore, and the new old stock may represent the only ...

(NOS) electronic components.

Description

The Phase 90 has an orange enclosure with a single control knob: * ''Speed'' - varies the speed of the phasing effect. The earliest "block" variants differ from the "script" variants in that they have a more pronounced sound (caused by the addition of a 24 kΩ feedback resistor) and the maximum speed is slightly higher (caused by the replacement of a 10 kΩ resistor in the effect's

low-frequency oscillator Low-frequency oscillation (LFO) is an electronic frequency that is usually below 20 Hz and creates a rhythmic pulse or sweep. This is used to modulate musical equipment such as synthesizers to create audio effects such as vibrato, tremol ...

with a 4.7 kΩ one); some later vintage units also have emphasis and de-emphasis circuits.

References

{{Commons Effects units