Phaser Pedals

A phaser is a modulation effect that sweeps a series of notches through your guitar's frequency spectrum, producing the swirling, whooshing sound heard on countless recordings. Kemper describes the family as "classic pedals like the Uni-Vibe creating signature sweeping soundscapes by shifting the phase of the signal"¹. Where a flanger or chorus works with short delays, a phaser works by shifting phase, and that difference gives it its own character: smoother than a flanger, more vocal than a chorus.

For a beginner, a phaser is one of the easiest ways to make a static chord part move and breathe. For an experienced player, the number of filter stages, the LFO shape, feedback, and where the pedal sits in the chain all change what it does. This page covers how the effect works, where it came from, the styles of phaser on the market, the controls you will meet, power requirements, and the questions worth asking before you buy one.

What a phaser does to your sound

A phaser shifts the phase of your input signal and mixes it back in with your dry signal². Because the shifted and dry copies cancel at certain frequencies, you hear notches in the tone, and because those notches move as the pedal sweeps, you hear a rising and falling, jet-like wash over the note. CNZ Audio describes its SPH-20 as providing "excellent note bending and sound wave shifting effects to add warmth and depth to your music with the possibility of extreme Phaser Effects"⁴.

The effect covers a wide range of moods depending on speed and depth:

• Slow and subtle: EarthQuaker Devices' Dan Epstein writes that at slower settings a phaser "adds majestic, wistful texture to slowly strummed open chords," enhanced by reverb or by placing the phaser in a delay's feedback loop³.
• Fast and deep: cranked up, the sweep becomes a pronounced wobble, the sound most people picture when they hear the word phaser.
• With dirt: Epstein notes that at low LFO speeds with distortion added, a phaser "adds thick texture and weight to riffs, useful for the lone guitarist in a heavy band"³.
• Pushed to extremes: Effectrode describes its tube-based Phaseomatic at rich settings as producing "intense, deep 'tunnel' phasing plus cosmic and spacious sound effects like 1950s 'B' science fiction movie soundtracks," and at subtle settings a natural-sounding vibrato and shimmering phasing⁵.

How a phaser works

The circuit is straightforward once you see the pieces. Function f(x)'s technical analysis explains that "the phase shifting in a phaser pedal is done via a series of all-pass filters"². Each all-pass filter, called a stage, shifts the phase of the signal across the frequency range without changing its level. The pedal mixes the filtered copy with the untouched dry signal, and where the two are out of phase they cancel, cutting notches into the spectrum. A low-frequency oscillator, the LFO, moves the notches up and down, which is the sweep you hear.

The number of stages sets the character. Function f(x) notes that "typically, phasers are configured in even numbers of stages (2, 4, 6, etc), but odd numbers of stages are also present in some pedals"². More stages means more notches and a more complex, textured sweep; fewer stages sounds gentler and more open. The classic four-stage circuit of the MXR Phase 90 is the reference point: Rocktron's manuals state that in its rack processors, a STAGES setting of 4 "produces a result similar to a vintage Phase 90, while a setting of '6' emulates other phaser" pedals⁶. That gives you a practical yardstick: four stages is the vintage sound, six stages is the fuller modern sound.

History and landmark phasers

The phaser pedal begins with Maestro. Gibson describes the Maestro Orbit as "a descendent of the very first phaser pedal ever produced - the legendary Maestro PS-1"⁷. The PS-1 established the format: a footswitched box with a rate control and a fixed number of stages. The Orbit carries the lineage forward as "an all-analog phaser pedal with 4-stage and 6-stage modes and a three-control layout"⁷.

From that origin the family tree spreads quickly:

• The script-era classics: the MXR Phase 90 and MXR Phase 45 fixed the four-stage sound in players' minds. Retro-Sonic's Phaser is "based on the famous 4-stage Script 90 circuit known for its classic phase tone"⁸⁹, and the Retro-Sonic 4-Stage Analog Phaser keeps that approach alive today.
• The univibe branch: the vibe pedal is really a phaser variant, covered in its own section below.
• Fuzz-plus-phase: PastFx's manual for its Jet Phaser notes that the original AP-7 "was unique for its time, incorporating a fuzz and phase circuit within one pedal"¹⁰, a combination later revived in the Warm Audio Jet Phaser.
• Long-running designs: Red Witch Pedals describes its Moon Phaser as a flagship pedal "used and loved by players over the last twenty years"¹¹.
• Modern multi-mode pedals: the Subdecay Quasar Phaser is a "multi mode phaser pedal"¹², and the Alexander Pedals Luminous Phaseshifter is described by its maker as "equal parts phaseshifter and swirly glowing haze machine"¹³.

Styles of phaser

Phasers on the market today sort into a few recognizable styles, and knowing which one a pedal belongs to tells you a lot about how it will sound.

A few of these deserve a note. The JHS 3 Series Phaser is described by JHS as "a versatile and easy to use six-stage phaser pedal inspired by the classic phaser circuits of the" past¹⁴, a good example of a modern pedal borrowing vintage architecture. The Death By Audio Moonbeam Phaser is "a stereo, multi-stage phaser like no other," letting you reshape the sound by choosing between modes¹⁵. And the Mod Electronics Phase/Off shows how flexible the format can be: its Stages switch "can change the Phase / Off from four-stage phaser to a two-stage phaser"¹⁷, so one pedal covers two classic depths.

The usual controls

Most phasers keep their control sets small. The two you will find on nearly every one:

• Rate (or Speed): how fast the LFO sweeps the notches. Slow settings give texture; fast settings give wobble.
• Depth: how far the notches move, from a faint shimmer to a full sweep.

Beyond those, makers add what their circuit needs:

The Duo-Phase, a two-phaser-in-one build, shows why sync matters: with Phaser B running in reverse against Phaser A, the two sweeps interact instead of simply doubling up¹⁸.

Where a phaser goes in the signal chain

BOSS's signal chain guide puts the standard order together: tuner first, then pitch, then compression and wah, with the wah pedal "directly after the tuner and before the drive section"¹⁹. Overdrive and distortion pedals come next, "stacked from lightest drive to heaviest distortion"¹⁹, then modulation, then time-based effects. Delay pedals sit after distortion "for cleaner and more even repeats," before reverb¹⁹. A phaser is a modulation effect, so the conventional home is after your drive pedals and before delay and reverb.

That said, placement is a matter of taste, and two alternatives are worth trying:

• Before distortion: the drive compresses the sweep into a more uniform, subtle movement, the thick-texture approach Epstein describes for heavy riffs³.
• In a delay's feedback loop: EarthQuaker Devices suggests that if you already have a delay pedal, you can "put the phaser in that effect's feedback loop to process the repeats," so each echo carries more phase than the last³.

At the end of the chain, looper pedals belong last, as BOSS's Lee Glynn explains, "as you will loop every possible signal and effect triggered"²⁰, and amp and cabinet simulators go at the very end when you are routing to a PA, interface or headphones¹⁹. A phaser belongs well before both.

Power needs

Most phasers run on the same 9V DC supply as the rest of a modern pedalboard, but the details vary and are worth checking before you buy. A few examples from makers' own pages:

Current draw is usually modest for analog phasers, but digital and feature-rich designs can pull more. Jim Dunlop specifies that its MXR Layers pedal "requires a 9-volt (300mA) center-negative power supply"²⁵, a reminder that a pedalboard supply sized for a handful of analog boxes may not cover every modern unit.

Phaser, flanger, univibe: telling the relatives apart

Phaser versus flanger. EarthQuaker Devices draws the line clearly: "flanging (whether via tape or a pedal) mixes a dry signal with a delayed one, then feeds the delayed signal back into the chain to create harmonic feedback," while "phasing, on the other hand, mixes two identical signals together," one dry and one through the all-pass stages³. A flanger's notches are harmonically related and its feedback gives it the characteristic jet swoosh; a phaser's notches are more evenly spread and its sweep is smoother and less metallic.

Phaser versus univibe. The vibe pedal is not a separate species so much as a particular phaser. Function f(x) calls the Dunlop Univibe "an optical phaser with no dry signal"², meaning the circuit drops the dry half of the mix that a standard phaser keeps. Jed's Peds describes the result: "in its simplest form a univibe circuit is a staggered phase shifter known for its throbbing, hypnotic pulse and lo-fi sweep"²⁶. If you want even, hi-fi movement, a standard phaser is the tool; if you want the pulse and lo-fi character of the classic vibe sound, look at the Dunlop Univibe and its descendants like the Sweet Sound Mojo Vibe and Dawner Prince Viberator.

Phasers on bass and in stereo

Bass players get real use from phasers, and some are built for the job. Recovery Effects says of its Pearl: "This pedal was created for bass, but you can also plug your guitar into it to make your low-end dreams come true!"¹⁶. The Pigtronix Bass Envelope Phaser is another dedicated option, and the general bass pedals category includes several more.

Stereo is the other frontier. The Maxon PH-350 Rotary Phaser, as a 2004 Better Guitar review republished by Maxon explains, is "really a stereo effects pedal. When using two amps, the phaser effect comes out the A jack, and the" dry signal comes out the B jack; with a single amp, the pedal "sends a mix of both the dry and effected signals through the A" jack²⁷. Two-amp setups like this spread the effect across the room in a way a mono pedal cannot.

Questions to ask when choosing a phaser

Before settling on a phaser, it helps to run through a few key points:

1. How many stages do you want? Four stages is the vintage Phase 90 sound; six stages is fuller and more modern⁶. Some pedals, like the Mod Electronics Phase/Off, switch between stage counts¹⁷.
2. Analog or digital? Analog phasers like the Maestro Orbit⁷ and tube designs like the Effectrode Phaseomatic⁵ have their own character; digital multi-mode pedals like the Subdecay Quasar¹² trade that for flexibility.
3. Do you need more than one mode? A multi-mode pedal covers several sounds in one footprint, which matters on a small board.
4. Mono or stereo? If you run two amps, a stereo phaser like the Maxon PH-350 splits effect and dry across outputs²⁷.
5. What power do you have available? Check voltage, polarity and current draw against your supply; the Vahlbruch 6-PHI-4's reversed polarity²³ and the MXR Layers' 300mA draw²⁵ show how much these details vary.
6. Where will it sit? After drive is the conventional spot³, but before drive and inside a delay's feedback loop both give different results³.

Questions