Keeley Electronics Octa Psi

The Keeley Octa Psi is an analogue fuzz pedal combined with a polyphonic pitch shifter and octave generator. The shifter and octaver can be used independently, and their position in the signal chain can be switched.

So, three effects that often sit together on a board, in the same box, but retaining the flexibility of discrete units. The ability to position each effect and switch it in and out of the signal chain independently is what makes this more than just a fuzz with a gimmick bolted on.

The fuzz is familiar territory — three voicing modes, a tone control, and stacked gain stages. The pitch shifter is where things get interesting: eight modes, each available in Up, Dual, or Down configurations, covering everything from subtle detune and minor second intervals to two full octaves up or down. All polyphonically, so chords track cleanly. The Blend control can also access major and minor voicings, making this a surprisingly coherent and musical pedal for something this flexible.

Fuzz Section

The analogue fuzz circuit uses discrete transistors to build stacked gain stages that push into hard clipping. Three voicing modes via the Fuzz Toggle shape the fundamental character:

• Scoop: Scooped-mids fuzz giving that classic hollow but aggressive sound.
• Punch: Adds a bass boost to thicken the low end — particularly useful alongside octave-down intervals to compensate for natural thinning.
• Psi: A distinctive synth-like fuzz with maximum undertones. Works particularly well with the Pitch section.

Tone

The Tone knob controls brightness and darkness across the whole signal. At noon you get the classic scooped-mids character. Clockwise adds treble and cuts bass. Counterclockwise rolls off the treble and fattens the low end. It works exactly how you’d expect.

Pitch Section

Eight pitch modes — hence the name — selectable via the Pitch encoder knob and modified by the Octave Toggle switch:

• DY — Detune: UP and DOWN give detuning from 0 to 30ms, creating a chorus-like doubling effect. DUAL gives both up and down simultaneously for a thicker, wider sound.
• M2 — Major 2nd: UP gives M2 up, DUAL gives M2 up plus a stacked fourth below, DOWN gives M2 down.
• M3 — Major 3rd: Standard major third intervals up, down, or dual.
• P4 — Perfect 4th: UP gives P4 up, DUAL gives P4 and P5 up simultaneously, DOWN gives P4 down with an added octave down.
• P5 — Perfect 5th: UP gives P5 up, DUAL gives P5 up and octave down simultaneously, DOWN gives P5 down.
• M6 — Major 6th: UP gives M6 up, DUAL gives a complex chord voicing (b5 up, bb7 up, #9 up — a Diminished 7th cluster), DOWN gives M6 down and #5 down.
• OCT — Octave: Up one octave, dual octave (up and down simultaneously), or down one octave.
• 2OCT — Two Octaves: UP gives two octaves up, DUAL gives two octaves up and one octave down simultaneously, DOWN gives two octaves down.

The Blend control sets the overall volume of the pitch and interval section. Pressing down on the Blend knob (Push-Blend) while rotating accesses additional voicings — in UP or DOWN positions, rotating fully clockwise switches between major and minor interval voicings. In DUAL mode, Push-Blend becomes a Volume Tilt control that adjusts the relative levels of the two pitch voices against each other.

Effect Order and Advanced Features

The factory default is Fuzz then Pitch. This is reversible — either by holding both footswitches simultaneously on the pedal itself, or remotely via the Control jack using a TS cable. The LED for whichever effect is first in the chain flashes three times to confirm the change.

Wet/Dry mix for the Octave section is switchable between All Wet and Wet + Dry by double-tapping the Push-Blend switch. The factory default is Wet + Dry.

Ramp Speed sets how quickly the pitch effect fades in — adjustable from approximately 5ms to 2 seconds by holding the Octave switch and turning the Blend control.

Bypass is selectable between True Bypass and Buffered Bypass. The factory default is Buffered Bypass.

Key Features

• All-analogue, transistor-based fuzz with stacked gain stages
• Three fuzz voicings — Scoop, Punch, and Psi
• Polyphonic pitch shifting across 8 modes, each with UP, DUAL, and DOWN configurations
• Two-octave range in each direction (-2 octaves to +2 octaves)
• Push-Blend function for major/minor voicing access and Volume Tilt in DUAL mode
• Independent Fuzz and Octave footswitches — use either or both simultaneously
• Switchable effect order — Fuzz into Pitch or Pitch into Fuzz
• Adjustable Ramp Speed for pitch effect onset (5ms to 2 seconds)
• TRS Control jack for expression pedal or external order switcher
• TRS Remote jack for remote switching of Fuzz and Octave bypass independently
• True Bypass or Buffered Bypass selectable
• Momentary or Latching footswitch modes selectable
• Wet + Dry or All Wet octave mix selectable
• 9V to 18V DC, 150mA, centre-negative — running at 18V gives increased fuzz headroom
• Made in the USA

Who Is The Keeley Octa Psi For?

The Octa Psi is for players who want a little more than conventional fuzz. Octave and pitch shifting sit naturally alongside fuzz, and the combination opens up shoegaze walls of sound, synth-like textures, and genuinely experimental territory. The more complex DUAL mode combinations generate chord-like sounds from a single guitar note — useful for solo players or anyone wanting to fill out a sound without backing.

If you need a power supply that supports selectable voltages to take advantage of the 18V option, the CIOKS DC7 v2 supports 9V, 12V, 15V, and 18V per outlet — an ideal pairing.

Watch The Octa Psi It In Action

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