The Xtonebox Carbon Booster is a boost pedal for guitar and bass built around a simple idea: a high-quality buffer feeding a genuine, original old stock J201 transistor. Pedal of the Day, reviewing it in September 2021, described the result as crisp, authentic tone that normalizes your pickup's signal for amplification in a technically correct way.1
It is a one-knob pedal. That single control handles both boost level and tone-shaping, which the review summed up as "providing gorgeous boost and tone-shaping with ease."1
How it works with your amp
The Carbon Booster behaves differently depending on where your amp is set, and Pedal of the Day spelled out both cases1:
- Clean amp: the pedal boosts your sound, lifting the signal without changing its character1.
- Dirty amp: it adds another layer of natural overdrive on top of what the amp is already doing1.
The review also noted that the boost "doesn't just raise the highs and mids," pointing to the full-range character of the J201-based circuit.1
Switching
The pedal uses true bypass with silent, clickless relay switching. Pedal of the Day noted this "helps to avoid any pops or clacks some pedals have when engaging," which matters if you run the pedal on a board with other effects and switch it mid-song.1
What reviewers said
Pedal of the Day's verdict was warm on the one-control format rather than apologetic for it: the reviewer cheered Xtonebox for creating a one-knobber that anyone can get behind, and for making it truly useful instead of boring.1
The review called the Carbon Booster Signal Boost "an essential tool for guitar" in its opening line, and the pedal was featured on the site on 20 September 2021.1
Videos
Pedal of the Day
Abel Franco
Questions
Is the Xtonebox Carbon Booster true bypass?
Yes. Pedal of the Day describes the Carbon Booster as true bypass with silent, clickless relay switching, which the review says helps avoid the pops or clacks some pedals make when engaged. That means the pedal is out of your signal path entirely when off, and the relay switching keeps the changeover quiet.
What transistor is in the Xtonebox Carbon Booster?
The circuit uses a genuine, original old stock J201 transistor, paired with a high-quality buffer according to Pedal of the Day. The J201 is a JFET transistor commonly associated with smooth, amp-like boost and overdrive tones.
Does the Carbon Booster work with a dirty amp?
Yes. Pedal of the Day says that with a clean amp the Carbon Booster boosts your sound, while running a dirty amp it provides another layer of natural overdrive. So the same pedal serves as a clean boost or a gain push depending on where your amp is set.
How many knobs does the Xtonebox Carbon Booster have?
One. Pedal of the Day calls it a one-knobber, with the single control providing boost and tone-shaping with ease. The review's verdict was that Xtonebox made a one-knob pedal that is truly useful instead of boring.
Sources (1)
- Xtonebox Carbon Booster Signal Boost, Pedal of the Day, 2021-09-20