The Acorn Amplifiers Circuit Fuzz is a two-transistor fuzz pedal with an unusual twist: a bonus boost circuit board mounted on the pedal's face, which Guitar World called the first stompbox effect with a "bonus" printed circuit board mounted on its face. The pedal was introduced in March 2020 and was reported available for $1491.
A fuzz with a bonus boost
The Circuit Fuzz keeps things deliberately simple on the outside. It has two controls, Volume and Fuzz, so it is nice and simple to use2.
| Control | What it does |
|---|---|
| Volume | Sets the pedal's output level1 |
| Fuzz | Sweeps from "light grit to full-on fuzzy chaos"1 |
Guitar World described level and fuzz knobs that sweep from "light grit to full-on fuzzy chaos with two simple controls"1. gearnews.com's writer went further on the range: "From overdrive to distortion to creamy fuzz, I expect this pedal will meet all your dirt-tone needs"2.
The transistor pairing is the heart of the circuit. Guitar World reported that "The dual transistor pedal boasts one silicon and one hand-picked NOS germanium transistor"1. That combination of a silicon device and a new-old-stock germanium one is what gives the pedal its two-transistor fuzz character.
For context on how a fuzz works at all: Jack Orman of the AMZ Guitar Effects Blog explains that a typical fuzz circuit has a gain stage to amplify low-level signals and a pair of diodes to clip the highly amplified signal, sounding like a compressor-limiter3. The Circuit Fuzz follows that basic idea with its transistors doing the gain and clipping work.
The pop-out boost PCB
The feature that sets the Circuit Fuzz apart from other fuzz pedals is the small boost circuit board mounted on the pedal's face. What the reports establish about it1:
- It is mounted on the pedal's face, a first according to Guitar World1
- It is designed to be clipped out of the face plate2
- It is intended to be built by the owner as a DIY project2
- The build instructions are free of charge2
There is also a hidden detail. Per the Acorn Amps owner in the comments on gearnews.com2:
"There's a secret under the clippable PCB if you remove it from the face plate"
The report does not say what that secret is.
The boost PCB is meant to be removed and built by the owner. If you buy one secondhand, whether the boost board has been built or is still stock is worth asking about.
What reviewers said
Reactions to the removable-PCB concept were mixed. gearnews.com's writer summed it up: "It's a neat idea, yes, but I'm not so sure it's a great one. This pedal may prove very tempting for collectors of pedal" curiosities, with the writer questioning the practicality of the pop-out PCB2.
Where it sits in Acorn's range
Acorn Amplifiers also makes other dirt pedals, including the Acorn Amplifiers Epstein Isn't Dead Op-Amp Boost/Distortion and the Acorn Amplifiers Acorn Vegeta Drive. Players comparing the Circuit Fuzz against other dirt types can also see the site's pages on overdrive pedals and distortion pedals, or boost pedals for standalone versions of what the Circuit Fuzz carries on its face.
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Questions
What transistors are in the Acorn Amplifiers Circuit Fuzz?
The Circuit Fuzz is a dual transistor pedal with one silicon transistor and one hand-picked NOS (new old stock) germanium transistor, according to Guitar World's report on the pedal's introduction. That mix of silicon and germanium clipping is a common way fuzz designs chase both aggression and a softer, vintage-flavored edge.
Can you build the Circuit Fuzz boost PCB yourself?
Yes. The boost circuit board mounted on the pedal's face is designed to be popped out and built as a small DIY project, and gearnews.com reported that the build instructions are free of charge. The writer also noted that there is a secret under the clippable PCB if you remove it from the face plate.
How much does the Acorn Amplifiers Circuit Fuzz cost?
Guitar World reported in March 2020 that the Circuit Fuzz was available for $149.
Does the Circuit Fuzz go from overdrive to full fuzz?
The pedal has just two controls, Volume and Fuzz. Guitar World described level and fuzz knobs that sweep from light grit to full-on fuzzy chaos, and gearnews.com's writer expected it to cover overdrive, distortion and creamy fuzz, meeting all your dirt-tone needs.
What is under the removable PCB on the Circuit Fuzz?
According to the Acorn Amps owner in the comments on gearnews.com's article, there is a secret under the clippable PCB if you remove it from the face plate. The report does not say what that secret is, so it remains a surprise for anyone who pops the board off.
Sources (3)
- Acorn Amplifiers' Circuit Fuzz boasts a bonus boost circuit board mounted on the pedal's face, Guitar World, 2020-03-24
- Genius or gimmick? The Circuit Fuzz pedal comes with a DIY pop-out boost PCB, gearnews.com, 2020-03-23
- Compression and Limiting in Guitar pedals, AMZ Guitar Effects Blog (muzique.com), 2003
