The swirling sound of the phaser is one of the most recognisable modulation guitar effects. Pioneered by the likes of Hendrix and Van Halen, this simple pedal has the capacity to warp your tone and add a wow factor to any riff. Find out how to harness it in this comprehensive guide.
The term “phaser” was originally used in some cases to refer to the popular tape flanging effect, whereby two reels of tape played the same signal but one was slowed ever so slightly at regular intervals. This created the “whooshing” effect that we today recognise as the flanger.
It was in the late 1960s, however, that the phaser came into its own. The Uni-Vibe effects pedal from Japanese manufacturer Shin-ei pioneered the phase-shift sound via an up-and-coming guitarist called Jimi Hendrix. By the early '70s, the phaser had become a readily available portable guitar effect and can be heard on all sorts of rock, pop, disco, country, fusion, RnB and prog tracks. The rest is history!
In this guide, we’ll explore the phaser effect’s unique qualities, the big names in the category, and how you can incorporate it into your sound, taking you one step closer to finding the pedal that’s right for you.
Before we begin, let's have a listen. Eddie Van Halen is known for his love of Phaser effects, among other things. Check out the intro to 'Atomic Punk':
Notice that the Phaser has an almost speech-like quality, as if your amp has a mouth that opens and closes. Although this iconic tone summarises the effect rather nicely, a Phaser can be tweaked to attain many weird and wonderful sounds!
A “phase” is a position on a frequency spectrum – when you see a waveform, you're seeing numerous phases beginning and ending when they hit the X axis.
The phase-shift sound is achieved by mixing two identical signals together: one signal is the dry input, and the other is fed through a series of all-pass filters, which boost or cuts frequencies to create peaks and troughs on the spectrum. The altered signal is then combined with the original. The recognisable swirling sound of a phaser is created by the low frequency oscillator (LFO) sweeping the filters across frequency spectrum.
Because of the movement caused by the LFO, your guitar goes in and out of phase. The frequency spectrums of the two signals match, then unmatch, then match, and so on, which is why the sound returns to “normal” every time the filters go round.
Phasers often use multiple all-pass filters in a chain – this is why some phasers have multiple “stages” to create complex overtones. In some cases, the output can also be partially fed back into the input, generating feedback that adds another dimension to the sound.
There are a few considerations when to use a phaser. As you've heard with our Van Halen example, it's an extremely bold, in-your-face effect! To make the most of its flamboyance, you'll need a little bit of extra know-how.
These are the most common controls that you’ll encounter on a phaser. Let’s take a closer look at what they do:
you may have already guessed that this controls the speed of the LFO that controls the position of the phaser's all-pass filters. A low rate gives you a slow-burning open-and-close effect, but when you increase it, your tone will reach new levels of swirling sci-fi glory.
Sometimes called “mix” or “wet/dry”, the level controls the amount of the effect applied versus the dry input signal. With the depth set to minimum, you’ll only get a faint suggestion of movement, but set it to full and your guitar will be virtually unrecognisable.
This controls the size of the peaks and troughs of the all-pass filters. The bigger they are, the more warped your guitar will sound.
Feedback controls the amount of output signal that’s fed back into the input. Similar to when you hold a microphone next to a speaker, the signal snowballs into a wash of noisy overtones. This can sometimes be used to dramatic effect, giving your sound an otherworldly distorted quality.
As with most modulation and time-based effects, a phaser traditionally sits at the back of a pedal chain, after everything except ambient effects like reverb and delay.
This means the effect will apply to everything in your chain so far, including distortion, EQ, filters and more. You can play around with this order to create more abstract sounds. It's worth noting that some guitarists prefer to put modulation pedals in the effects loop of their amp, if they have one. This ensures that the effect applies only to the cleanest version of your signal - but it's all down to preference.
These three modulation effects work in very similar ways. They all mix your dry signal with a filtered/detuned signal to create an abstract sound. Because of this, it can be easy to get them mixed up. Each one creates a modulated effect using an LFO, but tweaked slightly differently – so what is the difference between flanger, phaser and chorus? Here's a quick breakdown:
The phase of your signal's waveform is adjusted by an LFO, then mixed with the dry signal. The frequencies that are out of phase cancel each other out, causing a warped, wavy sound.
With flanger, the dry signal is mixed with a delayed signal swaying between 5-25ms The delayed signal is then fed back into the chain creating harmonic feedback.
And with chorus, your dry signal is mixed with a slightly detuned and delayed signal. The LFO controls the pitch of the delayed signal, and the further you push the pitch, the more wobbly the effect.
IN SUMMARY: A phaser uses an LFO to adjust the phase of your waveform, a flanger uses an LFO the adjust the delay of the signal, and chorus uses an LFO to adjust the pitch!
Next up, we're going to take a look at some of the big names in the phaser category. These pedals have helped define the effect itself, so chances are you may well recognise some of them.
This small selection is made up of just a few of our favourites, containing both vintage and abstract sounds and will fit neatly onto your pedalboard. Let's take a look:
EHX originally released the Bad Stone in the '70s, and it very quickly became a pedalboard staple. This updated & ultra-affordable version features a slower minimum rate, plus the super-useful manual shift control. This lets you cut the LFO movement out of the equation, giving you a static parked-wah phase sound!
Arguably the most recognisable of the bunch, the Phase 90 brought the phase-shift effect to the masses. With a single control (speed), this pedal does the rest of the work for you. Eddie Van Halen loved it so much, MXR made him his own signature version!
Boss's take on the Phaser offers far more flexibility for a little extra cash. It allows you to choose the number of all-pass stages to your phase sound, choose the sweeping direction (up or down, shepard tone-style), hard-edged step phasing for robotic sounds, and has a tap-tempo footswitch option! Killer!
This is the all-singing, all-dancing powerhouse! Offering unparalleled tweakability, expression pedal connectivity, 8 unique phase-shift modes, built-in signal boost and much, much more, the Empress Effects Phaser is the ultimate toolkit for guitarists who like their tone modulated!
Mini pedals are great because their compact size makes them ideal to fit onto pedalboards where space is a premium, and they often cost less than their standard-sized counterparts. The Tone City Summer Orange, Mooer Ninety Orange and Liquid, and Landlord FX Dutch Courage are all pocket-sized powerhouses, packing vintage and modern tones at incredibly tempting low prices.
Phasers are a little less common in today's music than they were in the '70s, so why not pack in a few extra phaser-adjacent effects while you're at it? The Mobius contains 12 different modulation types including a spacey phaser. The usual controls apply but you're able to store your own presets - 200 to be precise. Other neat features include manual tempo input and MIDI implementation. Similar to the Mobius, the MD-500 features MIDI in/out and user preset banks that can be easily toggled to and fro. However, this incredible all-in-one features 28 modulation types across 12 modes. As a result, there's a ton of customisation to be had with the MD-500's phaser.
If you're willing to widen your budget for the highest quality phasers, then there are a few options outside of the multi-fx realm. The Mr Black Twin Lazers K1 is pristine and lush across stereo sound. A nice touch with the expression pedal input to control any dials. Way Huge's analogue Attack Vector can get super frizzy and spitty thanks to a fast speed and feedback settings. The most artful pick is the Beetronics FX Larva, which has a unique morphing ability to transition or ramp up and down between two pre-set speeds, plus a freeze effect for quick changes on the go. The ultra flexible Strymon Zelzah combines four-stage and six-stage phasers that you can use separately, in series or parallel. Add in the stereo compatibility and you're going to have a huge sounding phaser on your hands.
Are you looking to add an exciting, pulsating effect to your riffs and melodies? Or some freshness and movement to your plucked cleans? Or would you like to wrap your audience in abstract, hypnotising tones? Each of the pedals we've discussed has its own character and special feature – check out our YouTube channel for some great phaser pedals, browse our phaser pedal catalogue, or come visit us at the Andertons Store to find the perfect stompbox.
Don't forget to check out the rest of our guitar pedal buyer's guides for more tricks and tips!
