The MXR Phase 90 is a phaser effects pedal introduced in 1972, the first pedal sold by MXR. It features one knob (Speed), an orange enclosure, and evolved logo designs (script then block). Production ceased in 1984 when MXR went bankrupt. Dunlop resumed production with added features: an LED and optional AC power supply. Pre-1981 units lacked LEDs, A/C adaptor jacks, and true-bypass switching. It was used on the first two Van Halen albums.
The Phase 90 is not just MXR’s first pedal — it’s the origin point of their entire design language.
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Logo Tells Time
Script logo or block logo tells you more about circuit timing than brand loyalty.
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Two Eras, One Name
Dunlop didn’t recreate the Phase 90 — they adapted it for modern boards, adding LED and AC power.
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What It Lacks, It Makes Up For
No LEDs, no AC jack, no true-bypass — and still the tone that launched Van Halen’s first two albums.
Worth your time?
Yes. Use the whole thing.
4.5/ 5
What works
single-knob phase sweep
cutting lead tone
organic modulation texture
What does not
true-bypass
LED
AC power option
depth control
Use it if
players wanting a singular, vintage phaser tone
those prioritising character over flexibility
Skip it if
players needing silent bypass
those requiring modern power or visual feedback
The written brief1 min read
What it is and what it was built for
A phaser effects pedal. MXR’s first product. Built to sit on a pedalboard and warp guitar tone with a single, sweeping motion.
How it works, in terms a player would use
It has one knob: Speed. Turn it to sweep the phasing effect faster or slower. No depth control. No feedback. No mode switch. It runs in series, not true-bypass — so your dry signal degrades when the pedal is off.
What it does better than anything else
It delivers a thick, swirling, organic phase sweep that cuts through a mix without distortion or noise. Nothing else from 1972 does this with one knob and zero compromise on character.
What it does badly
It cannot be subtle. It does not blend with dry signal. It lacks true-bypass, so tone suffers even when disengaged. It offers no control over intensity or resonance.
What people made with it
Eddie Van Halen used it on the first two Van Halen albums. Its sound defined the shimmer in early hard rock leads and clean funk rhythm parts.
Who should use it, and who should not
Players who want vintage MXR phase as a dedicated colour — not a toolkit. Not for anyone needing silent footswitching, LED status, or AC power out of the box.
Is it worth your time
Yes — if you want a single, unmistakable phaser tone and accept its limits. No — if you need versatility, silent switching, or modern power options.