JHS Pedals Fumble JFET Boost Effect Pedal

The Fumble exists because we made the biggest mistake in JHS history.

In May of 2025, we released the NOTADÜMBLË — our second solderless DIY kit pedal, containing two of the most coveted sounds from the Dumble universe. The overdrive side was correct: a boutique style overdrive built around the lead tone people associate with Larry Carlton, Eric Johnson, and Robben Ford. The clean side, however, was supposed to be a reverse engineered copy of the "A Box Later," a buffered effects loop device that Howard Dumble built sometime in the 1980s outside of his amplifier designs. John Mayer owns one of these obscure units and lent it to us. I replicated it, named it Box It Later, and that replica has traveled the world on John's pedalboards consistently since 2021.  I thought I put that circuit in the NOTADÜMBLË as the clean side.

I didn't.

A week after launch, while planning a Short Circuit episode video about the NOTADÜMBLË, I discovered I had used the wrong circuit. The clean side of the NOTADÜMBLË wasn’t the  “A Box Later”– it was something else entirely. Something I had also reverse engineered back in 2019 also for John, and then completely forgotten about. A separate Dumble preamp box that lived in a different archive location in our R&D storage. I had confused the two similar circuits and made a horrible mistake.

I made a video. I told everyone. We sold through the remaining  inventory, discontinued the NOTADÜMBLË V1 after our batch of 15,000 sold out, and refunded anyone who asked to return their unit.

Enter the Fumble.

WHAT THE FUMBLE ACTUALLY IS

The Fumble is a faithful production version of the other circuit I cloned for John: the Dumble BBC-1. Once the NOTADÜMBLË V1 was discontinued, customers started telling us how much they loved that circuit and how they wished it was sold separately. The Fumble is that exact circuit, now in its own compact enclosure with its own self-deprecating name, an $89 price point, and no kit to build.

Here is where the story gets stranger than fiction. While digging back through the original Dumble unit's history, we realized the BBC-1 isn't really a Dumble circuit at all. It's a JFET preamp lifted almost part for part from a Barcus Berry acoustic preamp made in the 1970s — the kind of small utility box that bridged piezo pickups into electric guitar amps in an era when nobody had a modern acoustic preamp. Howard cloned it. Put it in his own enclosure for a handful of local LA players. He then used the same JFET stage inside his amplifiers and called it the FET mode.

Which means the legendary Dumble FET sound — the one inside $200,000 to $400,000 amps — is a clone of a 1970s piezo preamp.

The Fumble is a clone of that clone of that clone. Three generations deep into one of the strangest chains of events in pedal history

WHAT IT DOES

The Fumble has two knobs, true bypass switching, and creates a particularly enhanced clean tone.

OUTPUT is your master volume. Turn it up for more volume.

INPUT is the one that surprises people. It is not a standard gain knob. It attenuates bass and input gain at the front of the circuit simultaneously. Fully right has no cut — consider it a bypass of the control. As you turn the knob to the left, bass and gain are gradually attenuated. Roll it down for a thinner, tighter response. Roll it up for a fuller, louder one. There is almost nothing else on the market that boosts in this way.

Type: Boost
Power Supply: 9 Volt DC Center Negative 5mA Power Supply (Not Included)
True Bypass/Buffer: True Bypass
Ins - Outs: 1 x 1/4" In, 1 x 1/4" Out
Stereo/Mono: Mono
Expression Out: No
Analog/Digital: Analog
Battery Connection: No