JHS Pedals Twin Twelve Channel Drive

The JHS Pedals Twin Twelve Channel Drive is an all-analog preamp pedal that puts the preamp and overdrive of the Silvertone 1484 "Twin Twelve" amplifier into a stompbox. JHS Pedals describes it as the first all-analog pedal to replicate that amp's preamp and overdriven tones, with discrete transistor stages standing in for the original tubes¹. Released in 2014 as the Twin Twelve Overdrive and reviewed by the press through 2015, it can serve as an always-on preamp, an enhancer for an existing rig, or a solo booster²³.

A Silvertone 1484 preamp in a pedal

The idea behind the Twin Twelve is simple: take a whole amp preamp and fit it into a pedal. Josh Scott of JHS Pedals explained the approach when the company revisited the pedal's history: "We took the Silvertone 1484 amplifier, and we basically built that exact amp circuit in a pedal instead, replacing the v[alve tubes with FET transistors]"². Each FET is hand-biased, and the conversion is what gives the pedal its character. Pedal of the Day's Adam E wrote that the tube-to-FET conversion "gives you more punch, a better dynamic range, and overall a true amp like feel"⁶.

Because it is a preamp rather than a single clipping stage, the pedal covers several jobs. JHS positions it as an always-on preamp, a rig enhancer, or a solo booster¹. The volume control works without clipping, so with the drive low it provides maximum clean headroom and boost when turned fully clockwise³.

Controls

The pedal keeps the amp's control layout, with four controls: Volume, Drive, Bass, and Treble, which is part of why it behaves like a preamp rather than a conventional drive box⁴.

Power: 9V in, 18V inside

The Twin Twelve runs on a standard 9V DC center-negative supply, but the circuit is designed around a charge pump that internally converts that 9V up to 18 volts¹. Delicious Audio described the charge pump as a special step-up transformer that lets the pedal run at 18V off ordinary 9V power⁵. Guitar World's Paul Riario noted that the internal 18V conversion "offers incredible touch sensitiv[ity]"³.

Is it a fuzz, a distortion or an overdrive?

It is all three at once, which is what makes it unusual. Guitar World's Paul Riario called it "a refreshingly unique preamp pedal that combines elements of fuzz, distortion and overdrive"³. JHS itself says the pedal handles amp-like overdrive tones, treble boosting, and edge-of-fuzz overdrive¹.

Riario described the sound at roughly midway drive settings as "a low-end growl and crumbly overdrive grind in the highs, with some velvety fuzz in the background"³. His overall verdict: "The Twin Twelve Channel Drive is a punchy stompbox that convincingly apes the saturated tones and speaker breakup sound of the prized Silvertone 1484 Twin Twelve amplifier"³.

Delicious Audio's reviewer heard something similar, and put it in terms many players will recognize⁵:

Delicious Audio, 2015⁵

The same review expected the pedal could earn a permanent place in the reviewer's gig bag⁵. At launch, Delicious Audio's news piece judged the $199 price "a little spendy" but thought the pedal did a fine job of the 1484's tones based on its NAMM debut demo⁷¹.

The Silvertone Twin Twelve behind the circuit

The source amp is the 1963 Silvertone 1484 Twin Twelve, a Danelectro-made combo sold through the Sears catalog in the early 60s. JHS describes the channel drive as designed after the vintage Silvertone amps made in the early 60s, with discrete transistor stages taking the place of the original tubes¹⁵⁶. Delicious Audio reported that the pedal duplicates the amp's classic Baxandall EQ, with improvements to make it more usable in pedal form, along with the original four-6L6 circuit design⁵.

The 1484 has since been revisited in pedal form by others. In 2022, Silvertone partnered with Jackson Audio to replicate the same "cult classic" amp as the Silvertone 1484 Twin Twelve pedal, which Guitar World reported can function as a studio grade preamp, booster, EQ or overdrive pedal depending on how the tone controls are set⁸. That Pedal Show's Mick grouped it among the gain pedals in a 2023 demo⁹. The JHS Twin Twelve remains the earlier take on the same amp.

One caveat for circuit builders: a widely shared "JHS Twin Twelve V1" layout on the tagboardeffects blog is not a copy of JHS's actual schematic. The blog's commenters found no evidence the layout's source schematic is the real JHS schematic; it is an individual's tube-to-FET conversion of a Silvertone amplifier circuit¹⁰.

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