The JAM Pedals "Achenbach" Boomster mk.2 is a high-fidelity boost and buffer that adds up to 16 dB of clean level while preserving the natural tone and feel of your instrument, according to JAM Pedals1. It is part of the Achenbach Series, a line of limited artwork pedals resulting from a friendship and collaboration between JAM Pedals and John Achenbach, and each one is a one-of-a-kind hand-painted piece1.
What it does to your sound
JAM Pedals describes the Boomster mk.2 as a clean boost and buffer built around Burr-Brown OPA2132 chips, delivering clarity, headroom and a musical response across every function1. The Level control provides up to 16 dB of clean boost, and at its minimum setting the active booster sits at unity gain, so it can be left on purely as a level-preserving buffer1.
In buffered mode, the OPA2132 circuit restores frequencies lost through long cable and pedal runs without adding brittle highs or changing the instrument's feel, according to the maker1. That makes it a candidate for players comparing dedicated buffers such as the TC Electronic Bonafide Buffer, the Empress Effects Buffer or the JHS Pedals Little Black Buffer, with the difference that the Boomster mk.2 also carries a full boost stage. For more on how buffers work and where they sit on a board, see Buffer Pedals, and for boost-only options see Boost Pedals.
Controls and modes
The pedal offers three voicings, selectable by the player1:
- High-cut
- Full-range
- Mid-boost
The footswitch supports both momentary and latching operation, so it works for a temporary lift or a sustained one1. JAM Pedals suggests three ways to use it: after drive pedals for a true volume lift, before an amp or overdrive for extra gain staging, or as a standalone buffer to restore detail across long signal chains1.
There is also an expression input: connect a standard passive 10 kΩ expression pedal to use the Boomster mk.2 as a traveling volume pedal1. That puts it in the same territory as dedicated volume units such as the Mission Engineering VM-PRO, though here the volume function rides on top of the boost and buffer.
Power
The pedal accepts 9 to 18V DC, center-negative, with a maximum current draw of 50 mA. JAM Pedals recommends an isolated supply, so a daisy chain shared with other pedals is not the maker's recommendation1.
Running the pedal at 18V is supported but optional; it works across the whole 9 to 18V range1.
The Achenbach Series and hand-painted artwork
The "Achenbach Series" is described by JAM Pedals as the result of a loving friendship that has developed through the years out of mutual respect, between the maker and John Achenbach1. Every limited artwork pedal is a one-of-a-kind hand-painted piece, and JAM Pedals states plainly that the pedal you receive will differ in detail from the photos shown1.
Custom artwork versions listed on the maker's page include "Dala", "Evil Green", "Mid Air" and "Relic"1. A separate page covers the JAM Pedals "Mid Air" Boomster mk.2, one of those artwork versions.
Price and buying terms
The list price is £294.00 GBP as of 25 October 2026, given by the maker in pounds sterling1. JAM Pedals ships the pedal DDP with 20% UK VAT and all duties included, with no extra charges on delivery, and free shipping within the UK1. The maker also offers a 30-day money-back guarantee with a full refund, no questions asked1.
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Questions
How much boost does the JAM Boomster mk.2 give?
The Level control provides up to 16 dB of clean boost. At its minimum setting the active booster sits at unity gain, so the pedal can also be used simply to preserve your level. JAM Pedals describes it as a high-fidelity boost and buffer that adds clean level while preserving the natural tone and feel of the instrument.
Can the Boomster mk.2 be used as a volume pedal?
Yes. JAM Pedals lists the pedal as a buffer, booster and volume, and says you can connect a standard passive 10 kΩ expression pedal to use the Boomster mk.2 as a travelling volume pedal. The footswitch also supports both momentary and latching operation, so it can be used for temporary or sustained level changes.
Is the Boomster mk.2 true bypass or buffered?
Both. Internal DIP switches select true or buffered bypass, so you choose which mode the pedal uses. In buffered mode, the OPA2132 circuit restores frequencies lost through long cable and pedal runs without adding brittle highs or changing the instrument's feel, according to JAM Pedals.
Does the JAM Boomster mk.2 run on 18 volts?
It can. The pedal accepts 9 to 18V DC, centre-negative, and JAM Pedals recommends an isolated supply. Maximum current draw is 50 mA. Running at 18V is optional; the pedal works across the whole 9 to 18V range.
What is the Achenbach series from JAM Pedals?
The Achenbach Series is a range of limited artwork pedals resulting from a friendship and collaboration between JAM Pedals and John Achenbach. JAM Pedals describes it as the result of a loving friendship that has developed through the years out of mutual respect. Each pedal in the series is a one-of-a-kind hand-painted piece.
Are the hand-painted Boomster mk.2 pedals identical?
No. JAM Pedals states that every limited artwork pedal is a one-of-a-kind hand-painted piece, and the pedal you receive will differ in detail from the photos shown.
Sources (1)
- “Achenbach” Boomster mk.2, JAM Pedals (www.jampedals.com)
