The JAM Pedals "Achenbach" Eureka! is a versatile silicon fuzz-distortion, part of the Greek maker's Achenbach line of one-of-a-kind hand-painted pedals. JAM describes it as combining a singing, dynamic midrange with the weight, grit and sustain of classic Muff-style circuits, with silicon transistors arranged to deliver a germanium-style dynamic midrange alongside full-bodied Muff-inspired fuzz-distortion1. If you know the maker's fuzz and distortion side, it sits in the same family as the Red Muck and Rattler pedals, though its own circuit leans toward the Muff camp.
Controls and the three-position bass switch
The Eureka! keeps its panel simple: three knobs and one toggle, with the bass switch doing the heavy lifting on low end1.
| Control | What it does |
|---|---|
| Gain | Sets saturation |
| Tone | Shapes the frequency balance |
| Level | Controls output level |
| Bass switch (3-position) | Middle: no bass boost; first position: adds low-end weight; maximum: adds still more bass |
The bass switch is the pedal's distinguishing control. In the middle position it applies no bass boost, leaving the circuit's natural balance. The first boost adds low-end weight, and the maximum setting adds still more bass; JAM notes that at that maximum setting the pedal can produce gated fuzz with a sufficiently strong input, which gives players a third, more extreme voice from the same toggle1. Between the Gain control and that switch, the pedal covers everything from a fuller rhythm drive to a saturated, gated lead sound.
Power, bypass and practicalities
The Eureka! runs on a 9V battery or a 9V DC center-negative supply and draws 8 mA, so it is an easy fit on any board, including a shared daisy-chain output. Bypass is true bypass1. Its footprint of 4.3 x 2.7 x 1.8 inches including jacks and controls, and a weight of 0.5 lb, keep it compact for a hand-painted pedal1.
JAM Pedals ships the pedal DDP with 20% UK VAT and all duties included, with no extra charges on delivery1. The regular price is listed as £284.00 GBP1.
The Achenbach artwork versions
The Achenbach line is JAM Pedals' limited artwork series, and the Eureka! follows the same idea: every limited artwork pedal is a one-of-a-kind hand-painted piece, and each unit differs in detail from the photos shown on the product page1. The custom artwork versions carry the same sound and differ only in their artwork. The versions JAM lists are:
- "Aww Man!" JLJ
- "Silver Sky"
- "Triocolore"
- "Lilac Window"
- "Relic"
So if you are comparing listings, the circuit and controls are identical across the range; the choice between a "Silver Sky" and a "Relic" finish is purely visual1.
Videos
JAM pedals
JAM pedals
JAM pedals
Questions
Is the JAM Pedals Achenbach Eureka! true bypass?
Yes. JAM Pedals lists the Eureka! with true bypass, so when the pedal is switched off your guitar's signal passes straight through without loading from the circuit. It runs on a 9V battery or a 9V DC centre-negative supply and draws 8 mA, which is light enough for almost any pedalboard power supply.
Does the Achenbach Eureka! use germanium or silicon transistors?
The Eureka! uses silicon transistors. JAM Pedals says they are arranged to combine a germanium-style dynamic midrange with full-bodied Muff-inspired fuzz-distortion, so the circuit aims for the responsiveness associated with germanium designs while keeping the practical advantages of silicon.
Is every Achenbach Eureka! painted differently?
Yes. Every limited artwork pedal is a one-of-a-kind hand-painted piece, and JAM Pedals notes that each unit differs in detail from the photos shown on its product page.
How much current does the Achenbach Eureka! draw?
JAM Pedals lists the current draw at 8 mA. The pedal runs on a 9V battery or a 9V DC centre-negative supply, so it sits comfortably within the budget of a single output on most daisy-chain or isolated power supplies.
Sources (1)
- “Achenbach” Eureka!, JAM Pedals (jampedals.com)
