The JAM Boomster Mk2 is a high-fidelity boost and buffer from JAM Pedals, an Athens, Greece based builder. It adds up to 16 dB of clean level while preserving the natural tone and feel of the instrument, and it fills three roles on a pedalboard: clean boost, standalone buffer, and volume pedal when paired with an expression pedal12.
What it does for your sound
JAM Pedals describes the Boomster mk.2 as "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"1. At its minimum setting the active booster sits at unity gain, so the Level knob starts at your normal volume and adds from there12.
Delicious Audio notes two ways to place it: after your drive section for a volume increase, or at the front end of an amp or drive pedals for added gain-staging2. The 9-18V power-input range gives variable headroom, so a higher supply voltage leaves more room before the boost clips2.
In buffered bypass mode, the buffer is designed to restore what long cable runs take away. Delicious Audio's write-up says the buffer will "instantaneously bring back frequencies compromised over long signal chains, without the unwanted top-end harshness and compromised mids," while retaining the original feel of the instrument2. Input and output are in phase3.
The controls: Level, voicing toggle and internal trimmers
The top panel is simple: one Level knob and a three-position voicing toggle, with the rest of the shaping done inside the box21.
| Control | What it does |
|---|---|
| Level | Up to 16 dB of clean boost; fully counterclockwise is unity gain12 |
| Voicing toggle, top position | High-cut: attenuates the top end, amount set with an internal trimmer12 |
| Voicing toggle, middle position | Full-range: keeps the response flat and open12 |
| Voicing toggle, bottom position | Mid-boost: adds focused midrange, amount set with a second internal trimmer12 |
| Internal DIP switches | Select true or buffered bypass12 |
The three voicings are tuned to work with a variety of instruments, as Delicious Audio puts it, and the two internal trimmers let you set exactly how much the high-cut position rolls off and how much the mid-boost position pushes2. Full-range is the neutral setting for a straight clean boost; the other two voicings tilt the boost toward warmer or more cutting depending on the amp and guitar1.
The footswitch supports both momentary and latching operation12. In momentary mode the boost is only active while the switch is held, useful for quick accents; in latching mode it stays on until switched off.
Power and connections
The Boomster Mk2 runs on 9-18V DC, center negative, and JAM Pedals recommends an isolated power supply1. Maximum current draw is 50 mA1. The wide voltage range is part of the design: Delicious Audio highlights the "9-18V power-input range for variable headroom"2.
The maker recommends an isolated supply for the Boomster mk.2. Running the boost at higher supply voltages increases headroom, and the pedal's hi-fi-grade Texas Instruments OPA 2132 chips are part of how it delivers up to 16 dB of clean level12.
The expression input is the connection that unlocks the third function. Connect a standard passive 10 kΩ expression pedal and the Boomster Mk2 becomes a traveling volume pedal12. Delicious Audio describes the sweep in detail: from 0 dB at the heel to the Level knob setting when the pedal is activated, or from 0 dB to unity gain when off in buffered bypass mode2. That makes it a smooth volume pedal option for players who want swell control without a dedicated volume pedal on the board.
Versions and hand-painted editions
The Boomster Mk2 is available in a standard version and in custom artwork editions, each hand-painted. The custom artwork versions listed by JAM Pedals include the "Achenbach" Boomster mk.2, the "Mid Air" Boomster mk.2, the "Dala" Boomster mk.2, the "Evil Green" Boomster mk.2 and the "Relic" Boomster mk.2, which is sold out3456.
Every custom artwork pedal is a one-of-a-kind hand-painted piece, so the pedal you receive will differ in detail from the photos shown34.
All versions share the same sound and the same feature set; JAM Pedals sums up the artwork editions as "Same sound, different artwork"45. The standard version carries a 30-day money-back guarantee from the maker: return it within 30 days of receipt for a refund, no questions asked1.
How it differs from the original Boomster
JAM Pedals positions the mk.2 as a development of the original Boomster rather than a side-by-side alternative. Delicious Audio quotes the builder's intent: "Our mission with the mk.2 version of the Boomster was to elevate it into a well-rounded boost pedal" with the features contemporary musicians expect, plus a standalone buffer2. The additions over the original are the three-voicing toggle with its internal trimmers, the selectable true or buffered bypass, the momentary/latching footswitch and the expression input for volume pedal use12.
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Questions
Can the JAM Boomster Mk2 be used as a volume pedal?
Yes. Connect a standard passive 10 kΩ expression pedal to the expression input and the Boomster Mk2 works as a travelling volume pedal. With the pedal engaged, the sweep runs from 0 dB at the heel to the Level knob setting; in buffered bypass mode it sweeps from 0 dB to unity gain when off.
Is the JAM Boomster Mk2 true bypass or buffered?
Either, your choice. Internal DIP switches select true bypass or buffered bypass. In buffered mode the maker says the buffer restores frequencies lost over long cable runs without top-end harshness or compromised mids, while retaining the original feel of the instrument.
What expression pedal works with the Boomster Mk2?
Any commonly available standard passive 10 kΩ expression pedal. JAM Pedals specifies a passive 10 kΩ expression pedal connected to the expression input to use the Boomster Mk2 as a travelling volume pedal.
Does the Boomster Mk2 footswitch work in momentary mode?
Yes. The footswitch supports both momentary and latching operation, so it can be held for a temporary boost or set to stay on.
How is the Boomster Mk2 different from the original Boomster?
JAM describes the mk.2 as an elevated version of the original Boomster, made into a well-rounded boost pedal with the features contemporary musicians expect, plus a standalone buffer. It adds the three-voicing toggle, selectable true or buffered bypass, and the expression input for volume pedal use.
Sources (6)
- Boomster, JAM Pedals (www.jampedals.com)
- Jam Boomster Mk2 Boost, Delicious Audio, 2023-08-17
- “Evil Green” Boomster mk.2, JAM Pedals (www.jampedals.com)
- “Dala” Boomster mk.2, JAM Pedals (www.jampedals.com)
- “Achenbach” Boomster mk.2, JAM Pedals (www.jampedals.com)
- “Mid Air” Boomster mk.2, JAM Pedals (www.jampedals.com)
