Posted by
Sep 13, 2021

KMA Audio Guardian of the Wurm

Earlier this year, I stood in front of a contemporary art installation from a Quebec-based artist asking me to trigger, via pedal, the end of the world. Irresponsible as I am, I stomped on it, but nothing happened (Quebequas are renowned for loving provocations). Today I am presented with a German guitar pedal by KMA Audio that promises to unleash “terror” at the pressing of a footswitch. Will it deliver?

Judging from the video reviews of metal-inclined YouTubers, the Guardian of the Wurm delivers alright!

This HM-2 inspired circuit marries KMA’s highly regarded WURM metal distortion with an intuitive, yet versatile and ultra-fast Noise Gate and a series of controls that allow its terrifying inner nature to be tamed and used to deliver pretty much any dirt tone for genres ranging from hard rock to epic doom.

What makes this pedal truly unique is its 4-band graphic parametric equalizer, something we haven’t seen before neither on a pedal nor on a pro audio piece of gear. This allows for incredibly precise EQ adjustment across the entire spectrum of your signal.

A 3-way clipping toggle opens the gates to as many voices:

• Silicon (Si) delivers the original compression, for rich harmonics and singing leads.
• Asymmetric (A-S) increases the headroom and gives you more grit by retaining complex harmonics,
• OFF position lifts the sound of the Diodes for a slight compression and way more clarity, perfect for baritone guitars or bass.

The useful Blend knob allows you to reintegrate some of the clean signal when a little bit of clarity and dynamics are needed.

On the right side of the pedal sits the Noise Gate section, based on a Blackmer® VCA and configurable via an internal DIP switch to change the trigger-source from pre- or post-Distortion or even pre-Noise Gate (useful when the pedal’s FX Loop is in use.

As if all these features were not enough, the KMA Guardian of Wurm also offers a Synced Mode that activates both the distortion and the gate at once. 

There’s a lot to chew here, the videos below should help you with sonic digestion. You can find other heavy gain stompboxes in our category of distortion pedals for metal.

Fusing together the powerful evolution of KMA’s highly regarded WURM Distortion with an intuitive, yet versatile and ultra-fast Noise Gate, GUARDIAN of the WURM is the perfect metal monster. From chugging hard-rock, droning doom metal and grinding Swedish death metal, the beast abides. But through its highly tweakable control set, the pedal can be tamed to provide impeccable clarity to your riffs, making this the definitive dirt pedal for metal, prog-rock, shoegaze, indie and beyond.

Calling a pedal legendary or a cult classic is often stretching the truth, but when it comes to the Boss HM-2 MIJ it’s absolutely on the money. We’ve never tried to hide the fact that the WURM Distortion is our unabashed sonic love letter to this filthy box of doom and gloom, taking the essential ingredients of this classic, while in the process developing a way more flexible metal-distortion pedal.

While WURM absolutely nails that Swedish death-metal chainsaw sound, the pedal is not all about that and is adept for so many other genres. To give you an idea, famous players like David Gilmour, Prince, Johnny Marr, Belinda Butcher, Lee Ranaldo, Daron Malakian and others have all made their mark with this style of distortion.

With GUARDIAN of the WURM, we’ve evolved our take on this venerable circuit and added a bunch of really useful new features. Whether you’re playing guitar, baritone, bass or synths through this pedal, we’re sure you’ll appreciate the immense flexibility on offer here. So let’s dig in.

We of course kept the iconic active HM-2 dual band EQ section, but added two more bands, giving a much wider range of tones to tailor your evil and gritty distortion sound. Each band now has a dedicated centre-frequency control on the front of the pedal, allowing you to quickly and easily change and fine-tune your tone.

The EQ-STYLE mode, now also on the front of the pedal, helps you carve out even more tonal variation. Selecting HM-II mode will get you that classic ‘chainsaw’ high-mids character. However, in KMA mode the EQ is a little more tonally balanced, less peaky and a bit wider in response. Selecting BOTH fattens and doubles up the tone stacking, allowing you to rank the LOWS and the HIGH MIDS and rip that Swedish forest even more to shreds.

To adjust the extent of drive compression, you can choose between 3 different clipping styles. Silicon (Si) delivers the original compression, for rich harmonics and singing leads. Asymmetric (A-S) increases the headroom and gives you more grit by retaining complex harmonics, while the OFF position lifts the sound of the Diodes for a slight compression and way more clarity, which is perfect for baritone guitars or bass.

Plus, the Clean Blend feature helps to preserve your natural core tone. Simply twist the BLEND control o mix in the original unprocessed signal, allowing the initial pick attack of your tone to breathe. It is also especially useful when running the GUARDIAN of the WURM into an already distorted high-gain amp.

When talking about high-gain, we all know drive circuits like this at full tilt can be noisy malice monsters. To get a grip on the potential noise floor, we designed a sophisticated, yet easy to use Noise Gate. This is based on a high-performance Blackmer® VCA and provides lightning fast and precise performance. Simply set the Threshold to taste via the GATE control and enjoy the silence. Fast palm-mutes? No problem. Decaying notes? Dead simple to accomplish. For even more tweakability, we fitted an internal DIP switch to change the trigger-source from pre- or post-Distortion or even pre-Noise Gate.

Pre-Noise Gate? Well, that’s because we added a TRS FX-Loop that works between the Distortion and the Noise Gate sections, allowing you to insert whatever fun noise-making pedals you might wish between them. You can also use this feature to place the Noise Gate section in your amplifier’s FX-Loop. Those who like to experiment with sound designs might even use the Noise Gate in other ways, for instance by using an external trigger source. No problem, the EXT TRIG jack hooks up to your source of choice.

In extreme settings, the WURM can sometimes begin to feedback, which can’t even be suppressed by the Noise Gate. To tame that high-frequency content, flip the internal dip-switch to activate the input filter to help smoothen things out. Yup, we did think of everything.

But wait, there is more! As the cherry on top, we added relay-based soft switches and also two different activation modes to suit the needs of different players.

“Independent mode” is exactly what it says on the tin. Both sides of the pedal can be switched on and off independently via the TERROR or TAME switches respectively. However, in “Synced mode” the entire pedal is switched on and off via the TERROR switch. In this mode the Noise Gate can also be switched in and out of the circuit as desired. Changing between modes is really simple to do. Just hold down both switches while connecting the pedal to the power supply, and you’re good to go. Once set, GUARDIAN of the WURM will remember the setting, even when powered off.

So here it is. Crank it up and you will feel the rage of the ancient WURM, while the GUARDIAN will help you tame that beast when needed, making GUARDIAN of the WURM your perfect pairing for an evil and gritty tone that never gets out of control… unless YOU want it to! \m/

Powered by an optional standard 9V DC (max.) PSU (negative center, 2.1mm, >150mA current draw).

Every pedal is designed, assembled, silkscreened, tested and numbered by hand in our small workshop. We use external manufactured PCBs to guarantee our high quality standard and keep the price of our pedals reasonable. The use of an indestructible powdercoated die-cast enclosure ensures a maximum durability.