The KMA Audio Machines WURM 2 is a high-gain metal distortion pedal with an active four-band EQ, built as a modern take on the classic and now sought-after original Boss HM-2 MIJ circuit1. KMA describes it as covering a wide range of metal-distortion tones, "from chainsaw, to plain evil and gritty"1. It was released on 29 March 2022 as a smaller, more pedalboard-friendly update of the company's earlier WURHM, designed and made in Germany2.
The HM-2 it draws on is the cornerstone of the Swedish death-metal "buzzsaw" guitar sound, a high-gain circuit whose Color Mix controls let you boost or cut mids3. The WURM 2 keeps that character but expands on it: KMA retained the iconic active HM-2 dual-band EQ section and added two more bands, giving a much wider range of tonal control than the original pedal offered1.
What it does and how it is controlled
The TERROR control dials in the distortion, which KMA describes with characteristic flair: "The TERROR control dials in all the malice and the evil distortion sounds you are searching for"1. Around it sit Volume plus four active EQ bands: Highs, Hi-Mids, Low-Mids and Lows, each with boost and cut range41.
| Control | What it does |
|---|---|
| Volume | Sets the output level |
| TERROR | Sets the amount of distortion1 |
| Highs | Active treble band |
| Hi-Mids | Active high-mid band, +/-8dB, variable from 950 Hz to 3.2 kHz5 |
| Low-Mids | Active low-mid band |
| Lows | Active bass band |
| EQ STYLE | Three-way toggle: HM-II, KMA or BOTH5 |
Each EQ band also has an internal trim-pot to change its center frequency, so you can fine-tune where each band sits without touching the external knobs1. The High-Mids trim pot ranges from 950 Hz to 3.2 kHz with a default center of 1.3 kHz, and it is active only in KMA EQ mode5.
The enclosure is compact with top-mounted jacks, smaller than the original WURM's, which makes it easier to fit on a crowded board1. It wears a black and orange color scheme that KMA calls reminiscent of its inspiration1.
The EQ modes: HM-II, KMA and Both
The EQ STYLE switch is the heart of what separates the WURM 2 from a straight HM-2 reissue. It is a three-way toggle that selects how the High-Mids band behaves5. On the original WURM this was an internal control; in the WURM 2 it sits on the front of the pedal so you can change voicing on the fly1.
| Mode | What you get |
|---|---|
| HM-II | The classic "chainsaw" High-Mids character, with a fixed internal center frequency, labeled "HIGH" on the original HM-25 |
| KMA | A KMA-designed H-MIDS EQ with an adjustable center frequency, effectively parametric; more tonally balanced, less peaky and a bit wider in response5 |
| BOTH | Combines both EQ styles, fattening and doubling up the tone stacking so you can ramp up the LOWS and the H-MIDS5 |
Gearnews summed up the two main voices: in HM-II mode "you get the classic 'chain saw' character of the high mids," while in KMA mode "the EQ is tonally more balanced, less pointed and slightly wider in response"2.
How it differs from the original Wurm
The WURM 2 is a revised version of the original WURM rather than a new circuit family. MusicRadar described it as "the Wurm returns in a smaller enclosure with a heap of features for high-gain, extreme metal misadventures"6. The changes KMA made:
- A smaller, more pedalboard-friendly enclosure with top-mounted jacks1
- Relay-based silent switching added to the true bypass5
- The EQ Style voice switch moved from an internal control to the front panel1
- Two extra EQ bands on top of the original HM-2 dual-band section1
Guitar World noted the practical benefit of the external switch, letting you flick between "chewier (HM-II) and slightly more balanced (KMA) distortions," with Both fattening the distortion with both voices7.
Is it a copy of the Boss HM-2?
It is an HM-2-based pedal, not a clone. KMA calls it a modern take on the original Boss HM2 MIJ pedal1, and the press coverage treats it as an interpretation: gearnews described it as taking "the legendary Boss HM-2 style circuit to the brink of insanity"2. The four-band EQ, the KMA voicing and the internal trimmers are all additions the original HM-2 never had1.
RockBoard's PedalPedia, which collects reviews and demos of the pedal, lists a review by AMAZONA (DE) and a demo video by Rabea Massaad, and its own verdict on the HM-2 MIJ sound is direct: "when it comes to the Boss HM-2 MIJ it's absolutely on the money"8.
Power and connections
The WURM 2 has no battery option. It runs only on a 9V DC center-negative 2.1mm supply1, and with a maximum current draw above 60mA per KMA's own specification1, it is not a good candidate for a low-current daisy chain.
The two published current-draw figures disagree: KMA's product page says ">60 mA max"1, while RockBoard's PedalPedia lists 50mA8. Either way, a standard 9V pedalboard supply covers it comfortably.
What reviewers said
Guitar Pedal X included the Wurm MK2 in its 2025 roundup of compact high-gain and heavy metal pedals, where Stefan Karlsson called it "yet another fantastic take on the HM-2, really expansive, with 3 core voicing Modes at its heart, as well as semi-parametric" EQ with internal frequency trimmers4. At launch, Guitar.com highlighted the face-mounted switch for choosing between the two EQ profiles or stacking both9.
Videos
KMA Machines
Science of Loud
The Pedal Zone
Questions
Is the KMA Wurm 2 true bypass?
Yes. KMA specifies true bypass with silent relay-based soft switching, so the pedal passes your clean signal untouched when disengaged and switches without pops or clicks.
What power supply does the Wurm 2 need?
It runs on 9V DC from a center-negative 2.1mm plug. KMA lists the maximum current draw as more than 60mA, while RockBoard's PedalPedia lists 50mA, so a standard isolated 9V supply with at least 100mA of headroom is a safe choice.
Does the Wurm 2 take a battery?
No. The pedal is powered only through its 9V DC center-negative 2.1mm power input, with no battery compartment, so you need an external power supply or a pedalboard power brick.
How is the Wurm 2 different from the original Wurm?
The Wurm 2 is a revised version in a smaller, more pedalboard-friendly enclosure with top-mounted jacks, relay-based silent switching, and the EQ Style voice switch moved from an internal control to the front of the pedal so you can change voicing on the fly.
Is the Wurm 2 a copy of the Boss HM-2?
It is a modern take on the original Boss HM-2 MIJ circuit rather than a clone. KMA kept the HM-2's active dual-band EQ character but added two more EQ bands, internal frequency trimmers and a KMA-designed voicing, so it covers the chainsaw sound plus tones the HM-2 could not reach.
What does the EQ Style switch do on the Wurm 2?
The three-way toggle selects the High-Mids EQ profile. HM-II gives the classic fixed-centre chainsaw character, KMA selects a more balanced, wider EQ with an adjustable centre frequency, and BOTH stacks the two voicings for a fatter, doubled tone stack.
Sources (9)
- WURM 2 - High-Gain Distortion with Active 4-Band EQ | KMA Machines, KMA Machines
- KMA Machines WURM 2 Distortion, gearnews.com, 2022-03-29
- TONEHOME, TONEHOME
- Guitar Pedal X, Guitar Pedal X, 2025-11-27
- KMA Machines Wurm 2 Distortion, Delicious Audio, 2023-01-10
- KMA Machines unleashes the Wurm 2, a fierce HM-2-style distortion pedal with expanded EQ options, MusicRadar, 2022-03-29
- KMA Machines slims down, revamps its Wurm distortion pedal, Guitar World, 2022-03-29
- Wurm 2 by KMA Machines, RockBoard PedalPedia, 2026
- KMA Machines’ WURM 2 offers chainsaw high-gain tones and beyond, Guitar.com, 2022-03-30
