Keeley Octa Psi Transfiguring Fuzz

The Keeley Octa Psi is a three-in-one fuzz pedal: a transistor-based analog fuzz, an octave generator and a polyphonic pitch shifter in one box, with two footswitches and two separate control sets, one for each effect¹. Keeley released it on September 24, 2024, after what MusicRadar reported as over three years of development by Robert Keeley and his team². Press coverage splits on the name: Guitar World calls it the Octa Psi Transfiguring Fuzz¹, while Pedal of the Day, MusicRadar and gearnews.com call it the Octa Psi Transfigurating Fuzz³²⁴. Both refer to the same pedal.

The idea is to cover octave fuzz and pitch shifting fuzz territory in one unit. Delicious Audio describes it as providing several modes of octave up, octave down, and octave up-and-down fuzz voicings, including two octaves down⁵. It sits alongside Keeley's other fuzz work such as the Moon Fuzz and the Dark Side Workstation, but the Octa Psi is the one built around pitch manipulation.

Fuzz, octave and pitch shifting in one pedal

The pedal is laid out as two effect engines. The fuzz side is a transistor-based circuit with its own knobs, and the octave and pitch side is a polyphonic shifter with its own controls, each with its own footswitch¹. On the face of the pedal, the pitch shifter's controls are marked in red and the fuzz controls in white, footswitches included, so you can tell the two sides apart at a glance⁵.

The pitch and octave side offers Up, Down and Dual modes, which Pedal of the Day says allows for creating nearly every harmonic interval, including power chords, stacked fourths and diminished chords³. MusicRadar describes the same section as a three-way toggle selecting octave up, octave down or dual modes². There is also the option to run All Wet or Wet/Dry modes, which Guitar World notes is there for what it calls especially crazy octave fuzz sounds¹.

Two features set the pitch side apart from a standard octave pedal:

• Momentary mode: with the octave and pitch footswitch set to momentary, you can create dive-bombs and bends that span multiple octaves².
• Adjustable ramp speed: the octave and pitch mode has an adjustable ramp speed for sounds akin to an expression pedal², and there is expression control access on the rear of the pedal⁴.

The controls

Each side of the pedal has its own control set. The fuzz side's knobs and switch shape the core fuzz tone, while the pitch side handles intervals and ramping¹³⁴.

Guitar Pedal X's review details the press-hold behavior on the fuzz footswitch: holding it flips the octave side between latching and momentary ramping modes, and holding it on power-up flips the pedal between true and buffered bypass⁸.

What Punch, Scoop and Psi do

The three-position toggle on the fuzz side selects between three EQ profiles, each a variation on the core fuzz tone⁴. Guitar Pedal X spells out what each does: Punch is a bass boost, Psi is maximum undertones, and Scoop is a scooped profile⁸. Premier Guitar's review found that this toggle "expands the potential of those three knobs exponentially"⁹.

Changing the effect order

The two effects can run in either order, and you switch between them by pressing and holding both footswitches at once³. That toggles whether the fuzz feeds the octave and pitch shifter or the shifter feeds the fuzz¹. Premier Guitar's review lists this as a hidden feature: you can instantly switch the effect order by simultaneously holding the octave and fuzz footswitches¹⁰.

What reviewers said

Reactions at launch were positive. Pedal of the Day called the pedal fun, with what it described as wonderful, warm, fuzzy octave tones and real magic when experimenting, and said it makes your guitar pickups sound enormous at any volume³. gearnews.com liked the versatility, noting the remote switching, expression control and effect order switching, and concluding that the demos all sound great and that it looks like a lot of fun to use⁴. On the fuzz voices themselves, gearnews found each mode offers a variation on the core fuzz tone with plenty of punch⁴.

Gearnews' Jef found the demos appealing, writing that "The demos all sound great, so I can see this being a lot of fun to use"⁴. He found the fuzz voicings had "plenty of punch"⁴, and liked the pedal's versatility, noting its remote switching, expression control and effect order switching³⁴.

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