Fulltone Fat Boost FB-3 Guitar Pedal, (Used)

The Fulltone Fat Boost FB-3 is a boutique-style clean boost pedal designed around a discrete Class-A FET circuit, intended to increase signal level while keeping the core character of the guitar largely intact. It can deliver up to around 35dB of gain and is known for high headroom before clipping, allowing it to push an amplifier harder without immediately introducing heavy distortion. The circuit is designed to behave in a more valve-like way than typical solid-state boosts, with soft clipping characteristics when driven harder.

Its control layout includes Volume and Drive plus tone-shaping controls for Bass and Treble, allowing the player to tighten low end or add brightness before the signal hits the amp or other pedals. This pre-EQ behaviour makes it useful both as a transparent volume lift and as a tone-shaping tool placed early or late in a signal chain. The design also supports a slightly compressed feel when pushed, which can help notes sustain more evenly at higher gain settings. 

The FB-3 is built with true bypass switching and a low-impedance output intended to drive long cable runs or downstream effects without significant signal loss. It is commonly used either to boost tube amplifiers into natural overdrive, to enhance solos with extra level, or to compensate for tone loss in complex pedalboards.