The JHS Notadümblë is a solderless DIY overdrive pedal kit from JHS's NotA-DIY line, following the Notaklön. Instead of arriving finished, it comes as a kit you assemble at home with no soldering, and it packs two Dumble-flavored circuits into one enclosure: an overdrive side based on Howard Dumble's amplifiers, and a clean/boost side123.
The story behind this pedal is unusual. The original V1, launched in May 2025, was accidentally built with the wrong clean circuit, and JHS discontinued it after roughly two weeks on sale453. A corrected dual-channel V2 followed, released around June 30, 202667.
The controls and modes
The original Notadümblë had two modes, Drive and Clean, selected by a slider switch on the front of the pedal rather than a footswitch2. Guitar World's reviewer noted that toggling between the channels mid-song meant bending down to move the slider9.
| Channel | Controls (V1) | What it does |
|---|---|---|
| Overdrive | Volume, EQ, Drive | Dumble-style overdrive, described by GuitarPlayer as offering Dumble's "violin lead tones"12 |
| Overdrive (internal) | Presence trim pot | Boosts or cuts upper-mid frequencies; a small trim pot inside the pedal, turned with a screwdriver13 |
| Clean (Boost) | Output knob | Sets the volume of the clean/boost channel2 |
The clean side is a J-FET-based circuit. Guitar World's Matt Lincoln found it "has the effect of bringing my Hot Rod Deluxe to life"9. Pedal of the Day described the clean mode as "a powerful preamp buffer pulled directly from John Mayer's personal stash of rare and never before replicated Dumble devices"2.
The wrong clean channel: BBC-1 instead of A Box Later
The Notadümblë's clean side was intended to be a copy of the Box It Later, a pedal JHS built for John Mayer and inspired by Dumble's A Box Later9. JHS borrowed Mayer's pedal during development and dissected it to replicate its sound14. But somewhere in the process, the schematics for the rare BBC-1 Dumble Boost, also known as the Basic Boost, got mixed up with the better-known A Box Later boost, and the production run shipped with the wrong circuit1516.
Josh Scott discovered the error on May 17, when he requested the original schematic from his head engineer17. JHS then owned up to the mistake, discontinued the V1, and offered refunds. The company also launched the BBC-1 circuit as a standalone pedal, the Fumble Mini Boost518.
The practical difference is smaller than the saga suggests. As Guitar World's reviewer put it9:
"the BBC1 and A Box Later are different circuits that sound very similar and do the same job."9
Both circuits were used by John Mayer15. The V1 sold through its remaining inventory and was discontinued after the batch of 15,000 sold out; the planned production run had already been halved from 15,000 units to 7,500, with the final batch released on Friday, May 23111714.
Buyers of the first version could claim a full refund by emailing support@jhspedals.com until the end of June 2025. That deadline has passed. JHS's current policy on the V2 states all sales are final, with no returns accepted under any conditions, though the product is covered by a limited liability warranty6.
Version 2: two footswitches and a moved Presence control
The Notadümblë V2, announced in late June 2026 and released Tuesday, June 30, corrects the circuit error and adds several features7. The clean/boost channel now uses the A Box Later circuit instead of the BBC-11167. Instead of the V1's channel slider, you get two independent footswitches, one per channel, for what gearnews called "a true two-in-one experience"56.
The V2 also moves the overdrive channel's Presence control from an internal trim pot to the face of the pedal as a regular knob, so high-end content can be set on the fly5. The overdrive channel carries Volume, Drive, an EQ low-pass filter, and the newly externalized Presence knob5. The kit adds an effects loop and an order toggle for the two channels611.
| Feature | V1 | V2 |
|---|---|---|
| Clean/boost circuit | BBC-1 (by mistake) | A Box Later / Box It Later56 |
| Channel switching | Slider switch2 | Two independent footswitches6 |
| Presence control | Internal trim pot13 | External knob on the faceplate5 |
| Effects loop | Not fitted | Added6 |
| Channel order toggle | Not fitted | Added6 |
The first V2 batch is limited to 6,000 units, but JHS says this is not a limited edition release and the pedal will be available indefinitely7.
What reviewers said
Guitar World's Matt Lincoln reviewed the original kit and found it "a versatile Dumble tone in a simple DIY box," concluding9:
"Personally, I would not be taking JHS up on their offer of a return, but rather keeping it on my board as an always-on solution."9
Guitar Pedal X's Stefan Karlsson, who assembled the original and reviewed the V2, called the upgrade "a brilliant exercise in upgrading the original" and praised the format itself: "I still think Josh Scott is a genius for introducing this format"1110. His verdict on the V2 was positive on the experience, with a caveat on sound quality: he thoroughly recommends it for the overall experience and the fun build process, but not for top-tier output quality10. He also judged the V2 great value at $11911.
gearnews found the price point excellent and the pedal's looks fantastic5. Pedal of the Day called the original "a DIY Pedal Kit that you can easily put together, and get great Dumble Amp-esque tones out of"13.
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Questions
Is the JHS Notadümblë a DIY kit?
Yes. The Notadümblë is a solderless DIY pedal kit, the second in JHS's NotA-DIY line after the Notaklön. You assemble it yourself at home with no soldering, and the V2 edition is a dual-channel kit with an overdrive side and a clean/boost side, each with its own footswitch.
Why was the first JHS Notadümblë discontinued?
The original V1, released in May 2025, was accidentally built with the wrong clean/boost circuit. Josh Scott intended to use the Box It Later circuit, based on John Mayer's A Box Later pedal, but the rarer Dumble BBC-1 circuit was installed by mistake. After discovering the error on May 17, JHS discontinued the V1 and developed a corrected version.
Can I get a refund for the original Notadümblë?
JHS offered a full refund to first-version buyers who emailed support@jhspedals.com by the end of June 2025. That window has closed. Guitar World's reviewer, who liked the pedal, said he would keep it on his board rather than take the refund.
Is the JHS Notadümblë true bypass?
Yes, Guitar World's review lists the original Notadümblë as true bypass. The clean side is a J-FET-based preamp circuit, so with the clean channel engaged the signal passes through active electronics rather than a hard-wire bypass.
Is the Notadümblë based on John Mayer's pedal?
Partly. The overdrive side is based on Dumble amplifiers, while the clean side was intended to copy the Box It Later, a pedal JHS built for John Mayer and modeled on Dumble's A Box Later. JHS borrowed and dissected Mayer's pedal during development. The V1 shipped with the BBC-1 circuit instead by mistake.
Sources (18)
- JHS Fumble JFET Preamp, Delicious Audio, 2026-06-23
- JHS Pedals NOTADÜMBLË Preamp Overdrive DIY Pedal Kit, Pedal of the Day, 2025-05-05
- FUMBLE - JHS Pedals, JHS Pedals, 2025
- JHS Pedals The Fumble: How to Market a $200k Mistake, gearnews.com, 2026-06-03
- Notadümble V2: JHS Pedals DIY kit fixes their mistake, gearnews.com, 2026-07-17
- NOTADÜMBLË V2, JHS Pedals
- JHS Pedals Notadümble V2, Guitar World, 2026-06-29
- JHS Pedals' Fumble is an $89 boost with a complicated history, MusicRadar, 2026-06-03
- JHS Notadümblë review, Guitar World, 2025-06-28
- Guitar Pedal X, Guitar Pedal X, 2026-08-10
- Guitar Pedal X, Guitar Pedal X, 2026-07-17
- “Two weeks after the release, I realized I made a huge mistake.” The JHS Notadümblë pedal was meant to mimic John Mayer's one-of-a-kind Dumble stompbox. It used the circuit from something even rarer, GuitarPlayer (www.guitarplayer.com), 2025-05-27
- Cosmodio Instruments Dumble and Dumbler (JHS NOTADÜMBLË Mod), Pedal of the Day, 2025-07-12
- JHS Pedals' Notadümblë has been discontinued after two weeks, Guitar World, 2025-05-27
- Guitar Pedal X, Guitar Pedal X, 2025-08-11
- JHS discontinues NOTADÜMBLË pedal after less than a month, guitar.com, 2025-05-23
- Guitar Journal: JHS Notadümblë Discontinued After 2 Weeks!, gearnews.com, 2025-05-27
- Guitar Pedal X, Guitar Pedal X, 2026-06-03
John Mayer
