Underground Accelerator

The Underground Accelerator is my answer to the question “what preamp should I use if I don’t know what preamp I should use?” It takes inspiration from the Alembic F-2B, so it has vaguely Fender-ish DNA, but with some tweaks to make it more flexible. The goal of the design was to get something that sounds good with little to no effort and is flexible enough to sit well in any situation with minor tweaking to a flexible EQ. Underground Accelerator has a moderate amount of gain so it is capable of overdriving when the gain is turned up, or you could keep the gain rolled way back for a nice fat clean, or you could go somewhere in the middle for a tasteful gritty clean. In addition to the familiar 3-band EQ, Underground Accelerator has an EQ bypass switch, which removes the EQ from the circuit and affords you an extra +30dB of gain. This can be ideal when you have an EQ somewhere else in your chain and just want some extra level on the output. Bass is where Underground Accelerator really shines, providing the rich bottom end missing in so many bass pedals, but it has also become a popular staple with guitarists, as it pairs well with an IR loader for a compact and convenient ampless rig to run direct.

The Summer 2024 revised edition of Underground Accelerator has the same great circuit as before, but now with upgrades like film capacitors in the audio path and soft-touch relay bypass switching.

As a tube pedal, Underground Accelerator requires a high amount of current to operate correctly. I recommend a 9-12VDC power supply capable of delivering at least 400mA. Using less than this can damage the power supply and/or the pedal.

Enclosure size: 4.8 in x 2.64 in x 1.58 in (122 mm x 67 mm x 39.6 mm)

Check out this demo from Jake Serek of Serek Basses!