JAM Pedals "Achenbach" Rattler Bass mk.2

The JAM Pedals "Achenbach" Rattler Bass mk.2 is a limited-artwork version of the Rattler Bass, a distortion pedal made for bass guitar by JAM Pedals. JAM Pedals says the Rattler Bass was created to capture the character and response of the company's original Rattler distortion, adjusted to preserve the low end, and that it delivers a rich, full-bodied distortion that works equally well for smooth sustain or aggressive grit¹.

The "Achenbach" part of the name refers to the artwork, not the circuit. JAM Pedals describes its custom artwork versions as the same sound with different artwork², so this pedal is electronically the standard Rattler Bass mk.2 wearing one-of-a-kind hand-painted paintwork. Every limited artwork pedal is a one-of-a-kind hand-painted piece, and the pedal you receive differs in detail from the photos shown¹.

A Rat-inspired distortion voiced for bass

JAM Pedals says the Rattler Bass is inspired by the sound of the late '80s ProCo RAT¹. Rather than copying the RAT's discontinued LM308 op-amp chip, JAM Pedals developed a proprietary discrete-component op-amp to preserve the open, dynamic and tube-amp-like feel players associate with that chip⁴. The company describes the Rattler as a bold, open and dynamic distortion that channels the fat, creamy voice of classic early-'80s circuits, and says the mk.2 keeps the tube-like response players love while adding modern reliability, clickless switching and expanded control over clipping and midrange⁴.

For a bass player, the point of the Bass version is that the voicing is adjusted to preserve the instrument's low end, where a guitar-focused distortion can thin things out. JAM Pedals positions it alongside other bass pedals in its line such as the Dyna-ssoR Bass and the Lucydreamer Bass¹.

The controls

The Rattler mk.2 generation carries a fuller control set than the original three-knob format. JAM Pedals lists the controls as Level, Gain, Tone, a Clipping switch selectable between asymmetrical and symmetrical, a Mid Boost footswitch and a Bypass footswitch⁵. Level sets the output, Tone shapes the frequency balance and Gain controls the fuzz intensity⁴.

The mid boost footswitch is worth a note for bass players: because it pushes mids into the distortion stage rather than after it, it changes how the pedal saturates, not just how it sits in a mix. The clipping switch similarly offers two characters of distortion in one box, a feature the original Rattler did not have⁴⁵.

JAM Pedals lists an input impedance of 500 kΩ and an output impedance of under 5 kΩ for the Rattler mk.2⁴.

Artwork versions and the original Rattler

The Rattler family has appeared in a series of custom artwork versions, which JAM Pedals describes as the same sound with different artwork⁴. Alongside the Achenbach, the guitar Rattler mk.2 has been offered in "Batkin", "Monterey", "Moonrock", "Ophis" and "Neurones" finishes, with the Neurones version sold out⁴. Every limited artwork pedal is a one-of-a-kind hand-painted piece, and the pedal received differs in detail from the photos shown⁴. On the bass side, the same artwork treatment appears on pedals such as the "Achenbach" Rattler Bass mk.2, a variant of the Rattler Bass with the same sound and different artwork².

The Achenbach artwork itself comes from a collaboration with an artist known for work on The Simpsons; JAM Pedals describes the original "Achenbach" Rattler ltd as its limited-edition, vintage-voiced distortion reimagined through that artist's artwork⁶. Guitarist Tim Miller, quoted on JAM Pedals' page for that pedal, said:

A PDF manual for the "Achenbach" Rattler Bass mk.2 is available for download from the pedal's product page on the JAM Pedals website¹. JAM Pedals also offers a 30-day money-back guarantee, refunding returned products no questions asked¹.

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