The Keeley Zoma Stereo Reverb and Tremolo is a stereo reverb and tremolo pedal from Keeley Electronics that combines what the maker calls the most popular "verbs and trems" into three mode pairs1. It is a digital reverb pedal2 built in a Beach Boys-inspired form factor with RCA Bakelite knobs and a crystal amp lens, and it carries the two effects that were the first ever built into amplifiers, tremolo and reverb, into the modern era12.
Pedal of the Day describes it as delivering "stereo, high-fidelity reverbs and luxurious tremolos" with "a wonderfully warm and inviting sound" and a gorgeous stereo field1.
The three modes: SS, PH and PV
Keeley has combined the most popular reverb and tremolo types into three fixed pairs, each selected together rather than independently12. Here is what each pair does:
| Mode | Reverb | Tremolo / Vibrato | What it does |
|---|---|---|---|
| SS | Spring Reverb | Sine Tremolo | Classic black panel amplifier spring reverb followed by sine wave tremolo at the power tubes1 |
| PH | Plate Reverb | Harmonic Tremolo | Bright, smooth plate reverb with phase-split, filtered tremolo1 |
| PV | Plate Reverb | Pitch Vibrato | Vocal smooth vibrato with other-worldly reverb1 |
Each half of the pair has its own character:
- Spring Reverb: tube amp spring reverb, simulating every detail of the classic vintage reverb sound1.
- Plate Reverb: bright, smooth reverb from a thin vibrating metal plate1.
- Sine Tremolo: simply adjusts the volume of the signal up and down1.
- Harmonic Tremolo: just like tube-amp harmonic tremolo, the guitar signal is phase-split and filtered, almost like a phaser1.
- Pitch Vibrato: bends the notes out of tune, with user control of how far and how fast1.
Note that you select the tremolo and reverb modes together, so you can mix and match those pairs, but the two effects share one mode selector rather than each having its own2.
Controls and hidden alt functions
The pedal carries separate tremolo and reverb footswitches, so each effect can be engaged independently, along with a MASTER LEVEL knob and the usual rate and depth controls2. On top of the visible controls, the Zoma hides three alt functions behind the REVERB/ALT footswitch:
| Alt control | How to set it |
|---|---|
| Reverb Decay | Hold the REVERB/ALT switch down while adjusting the Level knob1 |
| Reverb Tone | Hold the REVERB/ALT switch down while adjusting the Rate knob1 |
| Tremolo Boost Volume | Hold the REVERB/ALT footswitch down while adjusting the Depth knob1 |
The alt system means the small enclosure still carries six adjustable parameters: the visible rate, depth and level controls plus decay, tone and tremolo boost volume underneath them1.
History and versions: Silver and Custom Shop Sand
Keeley released the Zoma in October 2024 in two editions: a more limited Custom Shop Sand colourway and the Standard Silver edition reviewed here2. Pedal of the Day's unit is the silver enclosure, which the site calls "this silver beauty"1.
Guitar Pedal X places the Zoma in a line of Keeley releases, calling it a follow-up to the limited edition California Girls, I Get Around, and the more recent Halo Core2. Guitar World also described it at launch as a spiritual successor to the Keeley HYDRA Stereo Reverb & Tremolo.
The Zoma is generally considered a limited or limited distribution release, and Guitar Pedal X expects it to be discontinued at some stage2. Players comparing it against alternatives like the Strymon Flint and Fender Tre-Verb may want to treat availability as a factor.
What reviewers said
Guitar Pedal X's Stefan Karlsson called the Zoma "a particularly fine pedal" and "obviously competition for the Strymon Flint and Fender Tre-Verb," adding that it is prettier than both2. The same review calls it Keeley's most hi-fidelity pedal to date2.
"The Zoma is nevertheless a particularly fine pedal - obviously competition for the Strymon Flint and Fender Tre-Verb - while prettier than both."
Pedal of the Day's take is historical: the Zoma "brings the very first amp effects into the modern era and gives an unreal sonic experience"1.
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Questions
Is the Keeley Zoma stereo?
Yes. The Zoma is a stereo reverb and tremolo pedal, and reviewers describe its reverbs as stereo and high fidelity, with a gorgeous stereo field and a warm, inviting sound. It runs both effects in a stereo signal path rather than mono.
How do I change reverb decay on the Zoma?
Reverb decay is a hidden alt control. Hold the REVERB/ALT switch down while turning the Level knob to adjust decay. The same alt system sets reverb tone with the Rate knob and tremolo boost volume with the Depth knob.
Can I use the Zoma's reverb and tremolo separately?
Yes. The pedal has separate tremolo and reverb footswitches, so each effect can be switched independently. You select the tremolo and reverb modes together, which means you can mix and match the mode pairs rather than running each effect alone in any combination.
Is the Keeley Zoma being discontinued?
It is considered a limited or limited-distribution release that is expected to be discontinued at some stage, so it may become harder to find over time. It launched in October 2024 in a Standard Silver edition and a more limited Custom Shop Sand colourway.
How much does the Keeley Zoma cost?
Keeley webstore pricing at launch in October 2024 was $229 USD. It shipped in two editions, the Standard Silver and the more limited Custom Shop Sand colourway, at the same price.
Is the Zoma's reverb digital?
Yes. The Zoma is a digital reverb pedal from Keeley, offering spring and plate reverb simulations alongside sine, harmonic and pitch vibrato tremolo types.
Sources (2)
- Keeley Electronics Zoma Stereo Reverb and Tremolo, Pedal of the Day, 2025-11-09
- Guitar Pedal X, Guitar Pedal X, 2024-10-25
