Dumble Style Boost Circuit Read more..
The Fumble exists because Josh made the biggest mistake in JHS history.
In May of 2025, JHS released the NOTADÜMBLË — their 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 Josh, who replicated it, named it "Box It Later," and that replica has traveled the world on John's pedalboards consistently since 2021. Josh thought he had put that circuit in the NOTADÜMBLË as the clean side.
He didn't.
A week after launch, while planning a Short Circuit episode video about the NOTADÜMBLË, Josh discovered he had used the wrong circuit. The clean side of the NOTADÜMBLË wasn’t the “A Box Later”– it was something else entirely. Something Josh 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 the JHS R&D storage. Josh had confused the two similar circuits and made a horrible mistake.
A video was made. Everyone was told. JHS sold through the remaining inventory, discontinued the NOTADÜMBLË V1 after the 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 Josh cloned for John: the Dumble BBC-1. Once the NOTADÜMBLË V1 was discontinued, customers started telling JHS 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 and no kit to build.
Here is where the story gets stranger than fiction. While digging back through the original Dumble unit's history, JHS 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.
Use The Fumble Four Ways
Who This Is For
If you bought the NOTADÜMBLË V1 and loved the clean section, this is what was actually inside it. If you missed it, this is a beautifully simple JFET clean boost with a control set you won't find anywhere else. If you've ever paid a lot of money for a Dumble style boost from another builder, you should know the genuine article is simple. Uncomplicated. Affordable. It was always a version of an acoustic guitar preamp from the 70's.
Who This Isn't For
This is not an overdrive or a high gain pedal. If you want the lead tone half of the Dumble equation, you will want the NOTADÜMBLË V2 which updates the V1 with the the proper Box It Later clean section and the overdrive channel – in a single solderless DIY kit with two footswitches, an order toggle, and an added effects loop.
The Name
JHS have had the "Fumble" name and football helmet icon rolling around internally since April 10, 2012. It was originally going to be a Dumble style overdrive in their catalog, but the Moonshine took its place years ago. JHS never seriously revisited the Fumble project after then and the icon and rubber hand stamp went into a drawer for fourteen years. When all of this happened in 2025, the name was already there, waiting for the biggest fumble JHS had ever made as a company. Sometimes the universe hands you the punchline way in advance.
Features:
Dumble Style Boost Circuit
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