TWA Source Code

The TWA Source Code is an overdrive pedal from TWA (Totally Wycked Audio), designed by Susumu Tamura, the engineer who created the original Tube Screamer circuit for Maxon in 1979 and later designed the TS808 and TS9¹². TWA positions it as a next-generation 808-style overdrive: the classic TS soft-clip circuit, reworked with a custom op-amp, an 18V internal power stage, and a fourth control, Bite, that the original never had³.

The maker describes the result as preserving "the soulful midrange warmth of the classic green box while unlocking a new dimension of clarity, headroom, and harmonic richness"⁴. It is handmade in the USA, distributed by Godlyke, and launched in November 2025 at $299⁵².

A Tube Screamer circuit from its original designer

The Tube Screamer circuit was created by Maxon engineer Susumu Tamura in 1979, and it went on to become one of the most copied overdrive circuits in existence². Guitar Pedal X counts the Source Code as the latest step in that lineage, following the TS808, TS9, ST9, STL, TS10, TS5, TS9DX, TS7, TS808HW, TS-MINI and TS808DX².

The pedal's origin story is unusual. According to Guitar World's Paul Riario, the genesis came from Tamura's analysis of a friend's vintage Tube Screamer that produced an exceptional sound, traced to a rare Malaysian-made TI RC4558P op-amp. Tamura then developed a custom op-amp replicating its performance and its asymmetrical clipping properties, which became the pedal's "Magic IC"⁶. TWA says this op-amp gives the Source Code increased harmonic content and a more amp-like feel³.

Beyond the op-amp, the circuit differs from a stock TS in two ways the maker highlights:

• An all-new multi-transistor input buffer circuit, which TWA says preserves your guitar's original tone³.
• A 9 to 18V internal charge pump, which Guitar Pedal X credits with better headroom and fidelity².

The controls: Drive, Tone, Level and Bite

Three of the four knobs will be familiar to anyone who has used a Tube Screamer. The fourth is the pedal's main novelty⁸³⁶.

The Bite control is where the Source Code departs from the original design. TWA says that at higher settings it shifts from symmetrical to asymmetrical clipping, emulating the saturation and feel of high-gain tube amps³. Premier Guitar describes it as a control "that can mix in asymmetrical, tube-like clipping to the symmetrical clipping-based sound of the original"¹⁰. Guitar World's Paul Riario heard it differently in function: as a pre-gain input attenuator regulating how hard the input signal hits the amplification and clipping stages, with clockwise settings restoring clarity and note articulation and counter-clockwise settings delivering texture, chime and chunk⁶. On That Pedal Show, the hosts found that "that extra bite control drives a whole load more getting through the mid-range"¹¹.

Power: 9V boosted to 18V internally

The Source Code runs on a standard 9V DC power supply or a 9V battery³. Inside, an internal bipolar voltage regulator boosts the operating voltage to 18V, which TWA says delivers dramatically improved dynamics and increased headroom¹³. Premier Guitar's Tom Butwin walks through the same arrangement in his demo: typical 9V pedal power feeding an internal voltage regulator that raises the internal operating voltage⁹.

Other build details from the maker: top-mounted jacks for easier placement on pedalboards, mechanical true bypass switching, and low-profile matte-finished machined aluminum knobs³⁴. The enclosure is a sparkle green finish that Guitar Pedal X notes photographs poorly and "needs to be seen in the flesh"².

History and versions

TWA launched the Source Code in November 2025 as a four-knob TS-style overdrive handmade in the USA at $299³²⁷. Demand outpaced supply: the maker's main product page reports the pedal sold out, with orders carrying an approximate one-week build time before fulfillment¹. A B-stock version is also sold, described as brand-new pedals with flaws in the powder coating, listed at £191 against a regular price of £230; the maker notes these units will not be signed by Tamura⁴.

What reviewers said

Published reviewers were broadly positive, with the recurring theme that the pedal keeps the TS character while extending its range¹⁰⁷⁶.

• Guitar World's Paul Riario called it "One of the finest sounding TS808-style overdrives designed by Tube Screamer inventor Susumu Tamura"⁶.
• Premier Guitar's reviewer concluded: "It offers all the essence of the original, but it's the extra oomph and range that impresses"¹⁰.
• Guitar Pedal X's Stefan Karlsson, naming it among the best new boost and overdrive pedals of 2025, called it "an every way better tube screamer with more range and versatility," and said the Bite control's morph between symmetrical and asymmetrical clipping covers Boss OD-1 and SD-1 territory alongside "the best sounding TS808 flavour the author has heard from such a pedal"⁷.
• On That Pedal Show, comparing it against a TS9, the hosts found it had "Gobs more output" and a greater range of overdrive and clean output¹¹.

Premier Guitar's Tom Butwin demoed the pedal in November 2025, playing it and explaining its 18V internal boost, input buffer and Bite control, and calling it "the next evolution in the 808 style overdrive pedals"⁹.

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That Pedal Show covered the pedal twice: once in an October 2025 episode demoing five pedals (Source Code sounds begin at 32:40), and again in a July 2026 review alongside other overdrives¹²¹¹.

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