The Keeley OCTA PSI Transfigurating Fuzz is a three-in-one fuzz pedal released on September 24, 2024, combining an analog fuzz, an octave generator and a pitch shifter in one box1. MusicRadar called it "the ultimate combination of pitch-shifter, octave generator, and analogue fuzz" and reported that it took Robert Keeley and his team over three years to develop2. It was designed and built in the USA, with all jacks mounted on the top of its aluminum enclosure2.
The pedal is effectively two effects in series: an all-analog, transistor-based fuzz circuit of the Muff style, and a digital DSP section that handles octave up, octave down and dual octave modes plus pitch shifting34. Delicious Audio describes it as a "true do-it-all" not just for octave fuzzes but also pitch-shifting ones, with modes covering octave up, octave down, octave up-and-down voicings, and two octaves down3.
The fuzz section
The fuzz side is a transistor-based circuit with three knobs: Fuzz for gain, Level for output volume, and Tone32. A three-way toggle switch selects between three bass-response voices, each a variation on the core fuzz tone7:
The Tone knob interacts with the three-way switch, and the circuit uses hard clipping through stacked gain stages21. Delicious Audio notes the fuzz section can also produce distortion tones, not just full fuzz3.
The octave and pitch section
The pitch side is where the Octa Psi covers the most ground. A three-way toggle selects octave up, octave down or dual modes2, and Keeley's site states these offer access to harmonic intervals including power chords, stacked fourths and diminished chords7. The Pitch knob spans a two-octave range up or down, with "nearly every harmonic interval" in between and intervallic staging posts marked in red around the dial21. Delicious Audio counts 24 different pitch combinations in total, and notes the Pitch knob can also deliver a detuned chorus effect3.
A Blend control sets the wet/dry mix, and double-tapping the Blend knob switches the output between all-wet and a wet/dry blend2. There is also an adjustable ramp speed for the octave and pitch mode, which produces sounds akin to an expression pedal without one attached2.
Footswitches, effect order and momentary mode
The pedal has two footswitches, one for Octave and one for Fuzz, each serving its own effect9. Three behaviors matter to a player:
- Order switching: hold down both footswitches to toggle whether the octave and pitch section runs before or after the fuzz, so you can fuzz into the shifter or the reverse295.
- Momentary mode: the octave footswitch works in latching mode or momentary mode when held3. With the octave and pitch footswitch set to momentary, MusicRadar notes you can create dive-bombs and bends that span multiple octaves2.
- Bypass selection: a press-and-hold on the fuzz footswitch at power-up flips between true and buffered bypass8.
There is expression control access on the rear of the pedal7. Premier Guitar writes that "linking the Octa Psi with a standard expression pedal opens the door to a whole new dimension of pitch shifting mayhem," though an expression pedal is not required10.
The bypass is user selectable, so the same pedal can run true bypass on a small board or buffered bypass in a long signal chain. gearnews.com points out the buffered option makes it compatible with just about any pedalboard7.
History and design
Keeley released the Octa Psi on September 24, 20241. The pedal was over three years in the making and was designed and built in the USA2. Its circuit is Muff-style, with a fuzz section Keeley describes as thick-sounding analog transistor fuzz that can also produce distortion tones3.
What reviewers said
Early coverage was positive. gearnews.com's Jef wrote that "the demos all sound great, so I can see this being a lot of fun to use," and that the core fuzz tone "has plenty of punch"7. He also liked the design's remote switching, expression control and effect order switching, calling the effect versatile7.
Pedal of the Day's reviewer was blunt about the appeal:
"The Octa Psi Transfigurating Fuzz is FUN, there's no doubt about it"
The same review praised the all-analog, transistor-based fuzz circuit for making "your guitar pickups sound enormous at any volume"1.
Reviewers responded to the Octa Psi's playfulness. Gearnews' Jef wrote that "The demos all sound great, so I can see this being a lot of fun to use," and found the fuzz tone had "plenty of punch"7. The pedal's own launch coverage summed up the experience plainly: "The Octa Psi Transfigurating Fuzz is FUN, there's no doubt about it"1.
Videos
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Keeley Electronics
Keeley Electronics
Questions
Is the Keeley Octa Psi fuzz analog or digital?
It is a mixed design. The fuzz section is an all-analog, transistor-based circuit, while the octave and pitch-shifting section runs on digital DSP. Premier Guitar describes the pedal as effectively an analog fuzz and a digital octave section in one box.
Can you change the order of the octave and fuzz on the Octa Psi?
Yes. Press and hold both footswitches at the same time to toggle whether the octave and pitch section comes before or after the fuzz stage. This lets you run the fuzz into the pitch shifter or the pitch shifter into the fuzz.
Is the Keeley Octa Psi true bypass?
It can be. The pedal offers user-selectable true bypass or silent buffered bypass, and you flip between them with a press-and-hold on the fuzz footswitch at power-up. The buffered option makes it compatible with a wider range of pedalboards.
What does Psi mode do on the Octa Psi?
Psi is one of three bass-response voices on the fuzz section, selected by a three-way toggle alongside Punch and Scoop. Punch is a bass boost, Scoop scoops the mids, and Psi delivers what Keeley calls massive undertones for the heaviest low-end fuzz.
Does the Octa Psi have an expression pedal input?
Yes, there is expression control access on the rear of the pedal. Premier Guitar notes that linking it with a standard expression pedal opens up a wide range of pitch-shifting control, though an expression pedal is not required to use the pedal.
How much does the Keeley Octa Psi cost?
At launch in September 2024 it sold for an introductory price of $249 direct from Keeley, with street pricing around $269. A June 2025 Guitar World roundup lists it at $228. Sources disagree on the current figure, so treat $228 to $269 as the range.
Sources (10)
- Keeley Electronics Octa Psi Transfigurating Fuzz, Pedal of the Day (www.pedal-of-the-day.com), 2024-09-24
- “The ultimate combination of pitch-shifter, octave generator, and analogue fuzz!”: Over 3 years in the making, Keeley Electronics unveils the Octa Psi Transfigurating Fuzz, and it sounds wild, MusicRadar, 2024-09-24
- Keeley Octa PSI Transfigurating Fuzz, Delicious Audio, 2025-06-26
- Keeley Octa Psi Guitar Pedal Review, Premier Guitar, 2024-11-08
- Keeley Introduces Octa Psi Pitch Shifter and Octave Fuzz, Premier Guitar, 2024-09-24
- Guitar World's 30 favorite guitar pedals from the past 5 years, Guitar World, 2025-06-02
- OCTA PSI Transfigurating Fuzz! Keeley 3-in-1, gearnews.com, 2024-09-24
- Guitar Pedal X, Guitar Pedal X
- “It has taken us a long time to get this package perfected. I've got everything in here that I could dream of”: Keeley spent three years crafting the Octa Psi, Guitar World, 2024-09-25
- Keeley's Mind-Blowing Octa Psi Pedal, Premier Guitar, 2024-09-24
