Jhs Fumble Boost

The story behind the JHS Fumble pedal is truly unique! It all started with a mistake: JHS accidentally included the wrong circuit in its 2025 NOTADÜMBLË: a replica of the Dumble BBC-1 preamp—which itself was based on a 1970s Barcus Berry acoustic guitar preamp—instead of the “A Box Later” unit (which was actually a buffered effects loop that Howard Dumble sold as an external option with his amplifiers in the 1980s).
After openly informing buyers of this oversight (the product still sold 15,000 units), it turned out that this circuit was universally praised and was notably used by John Mayer. The Fumble is a meticulous reproduction of it.

The JHS Fumble is therefore a minimalist JFET preamp/clean boost designed for musicians who want to optimize their clean tone, gaining definition and body in a natural way, without altering the input signal.
The Input control is not a traditional gain control: it shapes how the boost affects the signal while simultaneously attenuating the bass frequencies and the input level. If you want a tighter, more refined sound, turn the knob to the left; for a fuller, more powerful sound, turn it to the right.
Either way, it’s the kind of effect you won’t be able to live without once you’ve tried it.