The Emerald Ox FX Chimeric Percolator is a handmade fuzz pedal built around the Harmonic Percolator circuit, the design behind the original Interfax HP-1, which Guitar.com's reviewer described as "an unwieldy-looking fuzz box with two slider controls"1. Where the original offered two sliders, Emerald Ox went the other way: the builder "created an extremely tweakable stompbox with eight knobs and four toggle switches," addressing what Delicious Audio's Paolo De Gregorio called the quandary of "perfecting the Harmonic Percolator circuit"2.
The Chimeric Percolator is discontinued. Guitar Pedal X's Stefan Karlsson noted in May 2024 that it had slipped past many players "while actively out, now discontinued"3. It was sold in limited batches, each adorned with art of a different mythical muddle of beasts, the first batch a lion-goat-serpent assemblage2.
What it does
The Chimeric Percolator is not a straight clone. Pedal of the Day's review found that "it contains elements of fuzz, filter, distortion and more," making it as much a shaping tool as a straightforward fuzz4. Delicious Audio put the intent plainly: "There is a knob or switch anywhere possible providing both of the most famous sound profiles as well as anywhere in between," and many extremes beyond2.
The idea behind the name and the artwork is the mixing of beasts: the builder, after comparing the varying tone of several original Percolator units, "decided to lay at your feet all the options so that you can choose your preferred Percolator sound (or three)"2. Because individual vintage Percolators are known to sound different from one another, the Chimeric Percolator gathers those variations into a single box.
The controls
Eight knobs and four toggles is a lot of panel, and not every control has been publicly identified. Delicious Audio noted that "Noise Generator was able to figure out a few controls in the videos below," and the identified ones are2:
| Control | Function |
|---|---|
| B (Balance) | Volume2 |
| H (Harmonics) | Gain2 |
| D toggle (up position) | Lifts the diodes2 |
| C7 toggle (middle position) | Removes the capacitor2 |
Delicious Audio also flagged how the panel behaves in practice: "The knobs are extremely interactive but supremely rewarding"2. Pedal of the Day's reviewer agreed, calling the pedal "a musical masterpiece" with "extremely interactive and supremely rewarding controls," while cautioning that unmusical settings are possible4. With this many controls, that is the trade: the range is wide, and not every combination lands.
How it compares
The Chimeric Percolator sits in a crowded field of Percolator variants. The Interfax HP-1 Harmonic Percolator is the original two-slider fuzz box1. Other takes include the Cat Box Customs Bean Machine, which Delicious Audio describes as "A variant of the Harmonic Percolator fuzz"5, and the BSRI Audio Hydrazine, "a modern interpretation of the Interfax Harmonic Percolator with updates to give players a wider range" of tones6. Fredric Effects adds "a switch to offer three different clipping options" to its version7. The Chimeric Percolator's eight knobs and four toggles made it one of the most option-laden of these, which is what its reviewers singled out.
Videos
ambienttrash
Pedal of the Day
Noise Generator
Questions
What is the Harmonic Percolator circuit?
The Harmonic Percolator is a fuzz design originally sold as the Interfax HP-1, a fuzz box with two slider controls. It has inspired many variants and interpretations from other builders, including the Bean Machine, the Hydrazine, the HP-X and the Chimeric Percolator, each of which takes the basic circuit and adds its own options or updates.
How many knobs and switches does the Chimeric Percolator have?
Eight knobs and four toggle switches. Delicious Audio described it as an extremely tweakable stompbox with that layout, with a knob or switch for nearly every possible variation of the Percolator sound. Only some of the controls have been publicly identified: B is Balance, which works as the volume; H is Harmonics, which works as the gain; and two of the toggles lift the diodes and remove a capacitor.
Is the Emerald Ox FX Chimeric Percolator still made?
No. Guitar Pedal X listed it as discontinued as of May 2024, with a last list price of $150. It was a handmade pedal released in batches, each batch decorated with art of a different mythical mix of beasts, starting with a lion-goat-serpent assemblage.
What do the B and H knobs do?
B stands for Balance and works as the volume control. H stands for Harmonics and works as the gain control. Both were identified by Delicious Audio, which noted that the Noise Generator channel worked out a few of the pedal's controls from demo videos.
Sources (7)
- Zander Circuitry Cafetiere review: A brilliantly tweakable take on the InterFax Harmonic Percolator, Guitar.com, 2022-06-14
- Emerald Ox FX Chimeric Percolator, Delicious Audio, 2024-08-21
- Guitar Pedal X, Guitar Pedal X, 2024-05-13
- Emerald Ox FX Chimeric Percolator, Pedal of the Day, 2022-11-25
- Cat Box Customs Bean Machine V2 Fuzz, Delicious Audio, 2022-10-05
- BSRI Audio + PEDALXCHANGE.com Hydrazine Harmonic Percolator Fuzz, Pedal of the Day, 2026-04-25
- Interfax Spec Harmonic Percolator, Fredric Effects
