The J. Rockett HRM V2, made by J. Rockett Audio Designs, is an analog overdrive pedal that re-creates the overdriven sounds of the Dumble ODS amp with the HRM EQ mod1. HRM stands for Hot Rubber Monkey, the name given to a variation found on some Dumble Overdrive Special amps that adds an extra EQ circuit, and J. Rockett's pedal is its interpretation of that circuit2. For a player, it is a compact D-style drive aimed at blues and rock tones, or anyone chasing what players call the Dumble sound3.
A Dumble-style drive in a pedal
Dumble amplifiers, and the Overdrive Special in particular, are rare, expensive amps whose overdriven sound has inspired a whole category of "D-Style" pedals. The HRM V2 sits in that category: Delicious Audio describes it as a D-Style overdrive, and MusicRadar calls it a compact D-style overdrive pedal that replicates the drive sounds of a Dumble equipped with an HRM EQ mod76.
What sets the HRM variation apart is the extra EQ circuit. Delicious Audio's buying guide explains that the Hot Rubber Monkey mod, found on some Dumble Overdrive Specials, adds an additional EQ stage, which in this pedal is impersonated by the Midrange control6. J. Rockett says the V2 features updated components and a redesign to provide an even more accurate HRM modded tone1.
The company's approach to the V2 was unusually thorough. Guitar World reports that J. Rockett got hold of an actual Dumble amplifier with the HRM EQ mod and spent two years listening to it to refine the sound, including sourcing some NOS (new old stock) parts for authentic sound2. MusicRadar relays the same story, noting that after two years with a modded Dumble, the builder says it captured more of the nuances of the sound7.
Controls, power and connections
The pedal keeps its control set simple: four knobs and a bypass footswitch2.
| Control | What it does |
|---|---|
| Level | Controls the overall output, very interactive with the Gain control6 |
| Gain | Controls the amount of gain, very interactive with the Level control6 |
| Top End | Controls the top end and helps tweak the amount of bite in contrast to the low mids3 |
| Midrange | Controls the "guitar" midrange and the thick low mids6 |
The Level and Gain controls are designed to work together rather than independently, so dialing in a sound means balancing the two6. Guitar World's review gives a useful starting point: with the Gain knob set at minimum, unity gain is around one o'clock on the Volume knob, and you start off in clean-with-grit territory2.
Power comes from a 9 volt negative tip adapter with a 5.5mm x 2.1mm jack1. Guitar World notes the adapter is not supplied, so plan on using your own supply2. J. Rockett lists the current draw as 18mA1, while Guitar World lists 30mA2. Either way it is a light load for a pedalboard supply. Connections are a standard input and standard output2.
The current draw is listed as 18mA by J. Rockett and 30mA by Guitar World. The two sources disagree, so if your power supply is tight on current, budget for the higher figure.
From the Hot Rubber Monkey to V2
The HRM V2 is the second version of J. Rockett's Hot Rubber Monkey. The original HRM, which Guitar World describes as the brand's interpretation of an ODS with an EQ modification, predates it2. Delicious Audio reported the upgrade to V2 in February 2025, citing tone improvements and NOS parts6.
Premier Guitar describes the V2 as an entirely different pedal from the first version, with different tone controls and a new design to match3. Guitar.com's review notes the specific renaming: the earlier version's "treble" and "fat" controls became "top end" and "midrange" on the V25. The V2 also uses NOS parts that J. Rockett says enhance the authenticity of the version6.
Within J. Rockett's range, the HRM V2 is one of several amp-in-a-box drives. The company also makes The Dude, a Dumble Overdrive emulator that itself received a V2 update, and Delicious Audio notes the builder has a solid reputation for no-frills amp-in-a-box pedals8. Another pedal in the same D-Style HRM territory is the Vertex Ultra-Phonix HRM, though that one is voiced toward EL-34 British sounds.
What reviewers said
Reviews of the HRM V2 were positive. Guitar.com's Richard Purvis gave it 9 out of 10 and wrote5:
"Never mind how close it gets to its near-mythical target, this is just a gorgeous-sounding overdrive with supreme touch-sensitivity5."
Richard Purvis, guitar.com5
He also found "a lot of tone-shaping power in those two EQ knobs, which have clearly been calibrated with meticulous care," and said the pedal "simply doesn't sound like a stompbox, infusing its warm crunch into your signal in a way that's 100% natural," with no obvious difference in dynamic response with it on or off5. His overall take: "there's not an ounce of gimmicky flab on the HRM V2, it's just a really fantastic dirt-bringer"5.
Guitar World's Trevor Curwen addressed the Dumble question directly. Not having compared it to an original Dumble, he found it "certainly in the ballpark of tonal qualities that one might expect from an original Dumble amp"2. Later, guitar.com's overdrive buying guide named the J Rockett HRM V2 its best Dumble-style overdrive9.
Videos
R.J. Ronquillo
Buddy Blues
TheGuitarGeek
Questions
How much current does the J. Rockett HRM V2 draw?
J. Rockett lists the current draw as 18mA. Guitar World's review gives 30mA, so the two sources disagree, but either figure is modest and easy on a typical pedalboard power supply. The pedal runs on a 9 volt negative tip adapter with a 5.5mm x 2.1mm jack.
Does the J. Rockett HRM V2 come with a power supply?
No. Guitar World lists its power requirement as a 9V DC adaptor, not supplied, so you need to provide your own. It uses a standard 9 volt negative tip adapter with a 5.5mm x 2.1mm jack, the same format most pedalboard power supplies use.
What does HRM stand for?
On this pedal, HRM stands for Hot Rubber Monkey, the name J. Rockett gave to its take on a mod found on some Dumble Overdrive Special amps that adds an extra EQ circuit. The mod itself was dubbed Hot Rubber Monkey, and the pedal carries the name.
Does the HRM V2 sound like a real Dumble amp?
Guitar World's reviewer, who did not compare it side by side with an original Dumble, found it certainly in the ballpark of the tonal qualities you might expect from one. Guitar.com's reviewer called it a gorgeous-sounding overdrive with supreme touch-sensitivity, regardless of how close it gets to its target.
Where is unity gain on the J. Rockett HRM V2?
With the Gain knob set at minimum, unity gain sits around one o'clock on the Volume knob, and at that setting you start off in clean-with-grit territory, according to Guitar World's review. From there, raising Gain and Level together pushes the pedal into heavier drive.
Sources (9)
- HRM V2 - J. Rockett Audio Designs, J. Rockett Audio Designs, 2025-11-06
- J. Rockett HRM V2 review, Guitar World, 2023-10-17
- J. Rockett Audio Designs Reinvents Their Hot Rubber Monkey, Premier Guitar, 2023-07-06
- HRM V2 B Stock, J. Rockett Audio Designs, 2026-10-12
- J Rockett HRM V2 review: even more authentic D-style overdrive, guitar.com, 2023-09-11
- J. Rockett Audio Designs HRM V2 D-Style Overdrive, Delicious Audio, 2025-02-10
- J Rockett Audio Designs is doing Dumble things again with the new-and-improved Hot Rubber Monkey V2 drive pedal, MusicRadar, 2023-07-04
- J. Rockett Audio Designs The Dude V2, Delicious Audio, 2023-01-06
- All gain, no pain: the 10 best overdrive pedals you can buy in 2026, Guitar.com, 2026-02-11
