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It’s hard to beat a classic, but the TWA Source Code overdrive, a leveled-up TS808-style pedal refined by the creator of the original Tube Screamer, has done just that. With the addition of a Bite control delivering clear articulation and texture, among other noticeable improvements, this may become the most go-to Screamer overdrive for guitarists who care about tone.
Pros
+
One of the finest sounding TS808-style overdrives designed by Tube Screamer inventor Susumu Tamura.
+
18V operation.
+
Plenty of features including Multi-transistor input buffer, Magic IC OpAmp, Bite control and +6 dB boost circuit.
Cons
-
It's an expensive pedal in a world of TS clones.
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I can hear many of you cry out, “Please God, not another Tube Screamer!” And yes, while I understand these pleas, here we are with yet another Tube Screamer variant to deal with. But hear me out! The Source Code, from TWA (Totally Wycked Audio), is one of the finest TS808-style overdrive pedals I’ve heard for many notable reasons.
(Image credit: Matt Lincoln / Future)
It’s not lost on me that the venerable Tube Screamer has become a punching bag of sorts because there are so many facsimiles, and all have been exhaustively compared and contrasted ad infinitum.
You could say that the Tube Screamer - or any other similar overdrive iterations - is essentially a “hammer” in a guitarist’s toolbox, to pound the front end of your amp for an enriching boosted tone. So, for the sake of argument, “How many times do we need to improve a hammer?”
Well, that’s where Susumu Tamura enters the chat. No, he didn’t invent the hammer, but Tamura is the creator and designer of the original Japanese Tube Screamer, and now, after an unrelenting examination into, yet again, overhauling his classic TS808 soft-clip circuit, Tamura, along with TWA, has introduced the Source Code overdrive.
The Source Code is a reimagined Screamer with a host of optimized improvements
Simply put, the Source Code is a reimagined Screamer with a host of optimized improvements like a newly developed “Magic IC” OpAmp, an added “Bite” control for more articulated sizzle, a multi-transistor input buffer circuit to preserve tone, and a few other enhancements that expand its sonic capabilities.
What this all means is the Source Code, in sum, may be Tamura’s masterpiece — a near-perfect TS808-style pedal from the designer of the Tube Screamer that could arguably be the new gold standard.
Tube Screamer Showdown with Totally Wicked Audio - YouTube
Type: Next-Gen soft-clipping TS808-style overdrive with Bite Control
Controls: Drive, Level, Bite, and Tone
Features: 18V operation via internal voltage inverter; “Magic IC” OpAmp for increased harmonic content and more amp-like feel; “Bite” control adjusts the amount of even-order harmonics present in the output signal; +6 dB boost circuit
Jacks: Top-mounted 1/4-inch Mono Input and Output jacks
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What’s improved is that the Volume control includes a +6 dB boost circuit (placed after the gain and tone-shaping circuit sections), which increases the pedal's output level without altering its fundamental tone.
What’s gone is the iconic Tube Screamer molded shell in favor of a chassis similar to TWA’s SH9 Scott Henderson Signature Distortion (another TWA pedal I adored). I appreciate that TWA is paying attention to the needs of many who value real estate space on their pedalboards by implementing top-mounted 1/4-inch input and output jacks with the 9V outlet in between.
(Image credit: Matt Lincoln / Future)
The pedal incorporates a new multi-transistor input buffer circuit, a noticeable improvement over the original TS808. Whereas the original used a single-transistor input buffer that significantly narrowed the audio's dynamic range, Source Code’s multi-transistor buffer reproduces the input signal more accurately and with less signal distortion.
Also attractive is the metallic green sparkle paint job and the bright LED that shines in a piercing white. Overall, the pedal feels durable and lightweight in its brick enclosure, and its low-profile, matte-black finished machined aluminum knobs have an even taper to make precise adjustments that stay in place. In other words, it’s built to last, because, hey, it’s made in the USA.
Usability
(Image credit: Matt Lincoln / Future)
Usability rating: ★★★★★
At the end of the day, the Source Code is a leveled-up Tube Screamer, so there’s not much of a learning curve to be intimidated by. The three main controls for Drive, Level, and Tone behave as expected when tailoring overdriven or boosted tones. What’s improved is that the Volume control includes a +6 dB boost circuit (placed after the gain and tone-shaping circuit sections), which increases the pedal's output level without altering its fundamental tone. For reference, setting the Source Code's Level control to 1 o'clock matches the maximum output level of a stock TS808, giving you an additional 1/3 of output level or “clean boost” by turning the knob further, which puts this pedal, for me, a 1/3 of an inch closer to making it onto my pedalboard.
The “ace in the hole” is the inclusion of a “Bite” control, which acts as a pre-gain input attenuator, regulating how hard the input signal hits the circuit's amplification and clipping stages. In essence, Bite serves as a handy secondary tone filter or gain control, providing dynamic changes throughout the entire drive spectrum by adjusting the amount of even-order harmonics within the output signal. For example, depending on where the Drive control is set, Bite noticeably restores clarity and note articulation (clockwise) or delivers texture, chime and articulate chunk (counter-clockwise).
Bite noticeably restores clarity and note articulation (clockwise) or delivers texture, chime and articulate chunk (counter-clockwise).
Finally, for a wider dynamic range and increased headroom, the pedal features an inverting charge pump IC that allows it to operate at 18VDC, providing a voltage swing of +/- 9VDC and a zero-volt reference, all derived from a standard 9VDC input.
Sounds
(Image credit: Matt Lincoln / Future)
Sounds rating: ★★★★★
Once you start introducing the Bite control, it becomes achingly clear that the “Bite” knob is the “silver bullet” that makes this pedal a secret weapon.
I've played through countless Tube Screamers, but the TS808 variants stand out as some of my top overdrives, primarily for their character, compression, and the pleasing warmth of their gritty breakup. For years, I’ve been fine with their inherent coloration, but since playing an unusual TS808 that stood head and shoulders above other Screamers tonally, I discovered why.
The genesis of the Source Code came from Tamura's analysis of a friend's vintage Tube Screamer that produced an exceptional tone due to a rare Malaysian-made TI RC4558P OpAmp. Inspired by this remarkable IC, Tamura developed a custom OpAmp that replicated its performance and unique asymmetrical clipping properties, resulting in the “Magic IC” incorporated within the Source Code overdrive.
With the Bite control completely rolled off, the pedal shares a similar tonal foundation to the TS808, but departs from it with the combined effort of its Bite control and "Magic IC" OpAmp, delivering a breathtaking, amp-like overdrive.
Once you start introducing the Bite control, it becomes achingly clear that the “Bite” knob is the “silver bullet” that makes this pedal a secret weapon. Once you start adding or subtracting the amount of rich harmonic content generated from the Bite control, you begin to wonder how you lived without it. Think of it as “bringing in the muscle” to a fight. At lower settings, it adds a chewy texture to the drive or boost, and past the halfway mark, it starts to sparkle with clarity and sinewy articulation. In other words, if you’re pushing a cranked amp, Bite becomes this muscular voice that fluently accentuates your pick attack, making each note pop with prominence.
Verdict
(Image credit: Matt Lincoln / Future)
I personally find the Source Code essential when paired with single coils in delivering that robust and stinging SRV-tone with snap. And alternatively, with humbuckers, it acts just the same, albeit with more brawn. What’s neat is the Source Code's slight compression manages to let the pedal breathe, resulting in a wide-open response. How good is it? Put it this way: I don’t use a Tube Screamer often, but if I did, the Source Code is the one I’ll be grabbing.
Guitar World verdict: It’s hard to beat a classic, but the TWA Source Code overdrive, a leveled-up TS808-style pedal refined by the creator of the original Tube Screamer, has done just that. With the addition of a Bite control delivering clear articulation and texture, among other noticeable improvements, this may become the most go-to Screamer overdrive for guitarists who care about tone.
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Ratings scorecard
Test
Results
Score
Build quality
Robust build and made in the USA.
★★★★★
Usability
Three familiar controls for Drive, Tone and Level, and a “Bite” control for increased articulation or texture. How did I live without “Bite” in my life?
★★★★★
Sounds
An unparalleled improvement of the mid-gain TS808 pedal that ticks every box in “clean” boost, burly overdrive and superb tone.
★★★★★
Overall
If you never cared for Tube Screamers, this superior TS808-style overdrive will change that notion.
The tried-and-true original overdrive on which the Source Code is based. You can’t argue with its classic blend of warmth, soft compression, and gritty breakup for boosting the front end of your amp, or pair it with other drive pedals for gain-stacking.
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The affordable NUX Drive Core DLX MKII is a versatile overdrive pedal. Its single rotary knob offers 8 distinct circuits for a wide tonal range. A Post Boost function, activated by holding the footswitch, provides up to 7dB of extra gain for solos, eliminating the need for a separate boost pedal.
Hands-on videos
Guitar World
Tube Screamer Showdown with Totally Wicked Audio - YouTube
Paul Riario has been the tech/gear editor and online video presence for Guitar World for over 25 years. Paul is one of the few gear editors who has actually played and owned nearly all the original gear that most guitarists wax poetically about, and has survived this long by knowing every useless musical tidbit of classic rock, new wave, hair metal, grunge, and alternative genres. When Paul is not riding his road bike at any given moment, he remains a working musician, playing in two bands called SuperTrans Am and Radio Nashville.
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