Acorn Amplifiers Solid State Preamplifier

The Acorn Amplifiers Solid State Preamplifier is a two-channel preamp pedal that puts the character of the 1980s Peavey Decade practice amp into a small stompbox. It is the latest release from Acorn Amplifiers, and it carries two foot-switchable tone channels, called "normal" and "saturated", that cover the clean and driven sides of the original amp's personality¹.

Where the bigger Acorn Amps Solid State is a full circuit recreation of the Decade, preamp and power amp together, the Solid State Preamplifier is the compact version: the preamp stage alone, in a 1590B aluminum enclosure, priced at $179¹². Acorn positions it as a studio tool for wiry and aggressive tones on guitar, bass, and even drums and vocals¹.

Two channels, four sound zones

The pedal's two channels are its core feature. Acorn describes the "normal" channel as delivering wiry, sparkling clean drive, while the "saturated" channel handles the amp's pushed, driven side¹. In Richard Purvis's review for Guitar.com, he found that the channel footswitch combined with a toggle gives four distinct voicings rather than just two:

His descriptions of each zone, from the same review:

The one criticism the review leveled at the pedal was practical rather than tonal: levels are sometimes mismatched when switching channels, so a player may need to ride their volume between the two modes².

Power, build and bypass

The Solid State Preamplifier is built for a normal pedalboard. It is true bypass, runs on 9 to 18V DC pedal power, and consumes less than 100mA of current, so it fits comfortably on most isolated supplies and even many daisy-chain setups¹. The 1590B aluminum enclosure is the same compact hammond-style box used for many small-format pedals¹.

Unlike its bigger sibling, the Preamplifier has no power amp section and no speaker outputs. The Acorn Solid State carries full 10 watt solid-state guitar amp circuitry, preamp and power amp, and its two separate output jacks let it work as a preamp in a pedal chain, as a standalone 10 watt amp into a speaker cab, or both at once³. The Preamplifier is the simpler proposition: it goes in your chain, shapes your tone, and feeds whatever comes next.

From the Peavey Decade to a pedal

The circuit's ancestor is the Peavey Decade, a small solid-state 10W combo that began life in the 1980s as a basic home practice amp⁴². Guitar.com's review calls it, affectionately, "a crappy little 1980 Peavey Decade practice combo", and that humble origin is exactly the point: the amp's cheap solid-state character became a sought-after sound².

The Decade's rise from practice amp to cult item has a documented trail. Gearnews reported in 2022 that Queens of the Stone Age used the Decade in the studio to get their tones, and that Acorn's Solid State pedal was built to capture it⁵. Guitar Pedal X later described the compact preamp as "Fantastic punchy compact preamp pedal based on Josh Homme's favourite Peavey Decade Combo"⁶.

Peavey itself has since joined in. The company now makes its own Decade preamp pedal, part of its Legacy Preamp Series of miniaturized Peavey amplifier circuits⁴, which means players comparing Decade-based pedals now have both the original amp's maker and the boutique recreation to choose from.

What the review said

Guitar.com published Richard Purvis's review of the Solid State Preamplifier on March 17, 2026, rating it 8 out of 10²¹. Beyond the four sound zones described above, the review's takeaway on the pedal's character was positive about its distinctiveness, with the channel-switching level mismatch as the main practical complaint².

For a player weighing it against other gain stages, the Preamplifier sits in a different spot from a typical overdrive or distortion pedal: it is a preamp, meant to impose the whole front-end character of a specific amp on your signal, rather than to push an amp you already have. And for bass players, Acorn's own description puts bass squarely in the pedal's intended use, alongside guitar, drums and vocals¹.

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