Prophecysound
Set your pedalboard to stun as we check out four 1970s-style phasers, revisited and revamped for the modern pedalboard
systems, Heptode, MXr & eHX
it’s the early 1970s and a new type of guitar pedal has appeared on the scene: the phase shifter or phaser. Up to that point the effects pedal scene was in its infancy. Wah and fuzz pedals were commonplace, but the only major modulation pedal was the Uni-Vibe, which was technically a four-stage phaser itself, but of a different design and with a distinctive sound that puts it into a category of its own rather than be lumped in with pedals that are actually called phasers. The new phaser pedals, arguably, heralded the birth of the stompbox as we now know it today and would hold sway as the only mass-produced type of modulation pedal available until the chorus and flanger appeared later in the decade.
Phasers give a swirl or whoosh (a swoosh, perhaps?) to the sound. There’s not the space here to go into the theory, but the sound – in which different frequencies are emphasised and de-emphasised – is a result of notches in the frequency response being swept up and down. Phasers can be categorised by the number of shifting stages they use: the more stages, the more notches. Each pair of stages adds one more notch.
How did the phaser come about? Well, the design started off in life (like the Uni-Vibe before it) trying to replicate the sound of a rotary speaker. Audio engineer and synth pioneer Tom Oberheim has stated that he was inspired by George Harrison playing through a Leslie speaker on a Beatles album and decided to make something to recreate that sound. When it came down to it, he actually found the Leslie sound too complex to recreate, but in the process came across a phase shift circuit that he thought sounded “really cool” in its own right. From here, he designed the Maestro PS-1A unit, which he describes as the first phase shifter that was available for musicians.
audio engineer and synth pioneer Tom Oberheim was inspired by George harrison playing through a Leslie speaker and decided to recreate that sound…
The Maestro was a simple unit with just three buttons for different phase speeds. It was used by John Paul Jones of Led Zeppelin for his keyboards, and guitarists Steve Howe (Yes) and Joe Walsh among others, but perhaps its greatest use on guitar was by Ernie Isley on the Isley Brothers’ That Lady, released in 1973, where its phasing mixed with fuzz delivers liquid synth-like lead lines that still sound fresh today.
While the PS-1A was a large unit, the next phaser to really make a splash was the MXR Phase 90: a fourstage phaser designed by Keith Barr in 1974, which put phasing into a more manageable underfoot size and set the style for modern effects pedals. This little box had a single rotary knob to change the speed of the phasing, and was pretty much the go-to phaser for pro guitarists in the mid-70s, used by many names. It was towards the end of the decade, in 1978, that one of its best known exponents, Eddie Van Halen, emerged using it on tracks such as Eruption. MXR also produced the two-stage Phase 45 and the six-stage Phase 100 (used by Keith Richards, notably on the recording of The Stones’ Some Girls album in 1977).
MXR pedals were relatively expensive items back in the 1970s, but there was soon a four-stage phaser available for those on a tighter budget. Electro-Harmonix was probably the most prolific of pedal designers in the 1970s, with a massive range of exotically titled pedals. The company came up with the David Cockerell-designed Small Stone in 1974/’75. Based around Operational Transconductance Amplifiers (OTA) rather than the FETs of the Phase 90, the Small Stone was easier to mass produce and sold in truckloads. Jonny Greenwood of Radiohead is one notable contemporary user. Also in EHX’s 70s roster was the larger Bad Stone, which featured a different circuit design, and the mains-powered Polyphase.
Phasing into the Future
While many companies produced phasers in the 1970s, (and there are others that deserve a mention here such as Roland’s AP-7 Jet Phaser with its built-in fuzz), there’s one particular phaser that’s held in very highesteem and commands prices in excess of £1,500 if you can find one. The Musitronics Mu-Tron Bi-Phase’s designer, Mike Beigel, had the smart idea of putting two six-stage phasers in one box with an optional foot controller. This is the phaser used on many of Lee Perry’s classic reggae productions, but has a sound that will also be familiar to Smashing Pumpkins fans as it’s all over their Siamese Dream album. Musitronics also produced The Phasor II, a smaller pedal that’s effectively half of a Bi-Phase.
Nowadays, there are numerous modulation pedals seeking our attention. Besides chorus and flanging we have very accurate-sounding Uni-Vibe recreations and dedicated rotary speaker emulation pedals, but there is still a role for the phaser’s swirl, whoosh or warble, and if you want that 70s sound, it’s still up for grabs.
So, here we have four classic phasers: the latest repro from MXR, Electro-Harmonix’s compact and pedalboard-friendly version of its Small Stone, plus boutique reproductions of the Maestro PS-1A and the Mu-Tron Bi-Phase from Heptode in France and Prophecysound Systems in Australia respectively. Time to squeeze into those loon pants…