Boss HM-2

Boss HM-2

The Cabinet’s contents are not for the faint of heart. In it, we have countless relics from eras past, including many fine overdrives and other tonal enhancers, some of which are extremely sought-after by aficionados and collectors alike. And we here at Catalinbread will take these artifacts for an occasional test drive. But sometimes you need something with a little more bite. Why reach for a scalpel when only a chainsaw will do?

Enter: the Boss HM-2 Heavy Metal, known affectionately as the progenitor of the “chainsaw sound.” Before we get to what it means to sound like a chainsaw (Jackyl notwithstanding), let’s talk about heavy metal itself.

The genre of heavy metal has meant many things to many different people, and even today, critics argue over the world’s first metal band, with some folks claiming Led Zeppelin as a heavy metal act. Fast-forward to the present, and today’s metalheads vehemently denounce such nonsense. Metal has evolved so much since the late ‘60s that the harbingers are virtually unrecognizable. The genre of “heavy metal” didn’t even catch on by name until bands like Judas Priest and Quiet Riot began releasing records that talked about metal right in their album titles. But once it solidified its signature sound with loud, heavily distorted guitars, pedal companies saw dollar signs. The first pedal out of the gate was Boss’s offering, in 1983—the same year that Ozzy first barked at the moon and Metallica killed them. All of ‘em.

At first, metal players didn’t know what to think. As is often the case with gear named after specific genres (DOD’s Grunge and Death Metal et al), nobody uses those pedals to write songs within the same genre—it’s an unspoken rule. Players like Eric Clapton and David Gilmour bought them and immediately strapped them to their pedalboards. This did Boss’s marketing department no service as they tried to curry favor with burgeoning heshers.

The HM-2 chugged along until 1991, when Boss pulled the plug, only to replace it with the HM-3 Hyper Metal. But one important event in the HM-2 timeline occurred in June of 1990, when Entombed released Left Hand Path, which saw a burly guitar tone front-and-center across 47 minutes of scathinc Swedish death metal. At the time, people saw Left Hand Path for the genre cornerstone it is, rather than a hallmark in tonal achievement. Sales of the HM-2 withered, with Entombed’s fans silently wondering how such an ungodly tone was achieved.

Boss HM-2

It wasn’t until 2008, when YouTube hosted a video by Daniel Ekeroth—the person who quite literally wrote the book on Swedish death metal—where he explained how to get the tone from Left Hand Path. Some 18 years after the album’s release, nobody had forgotten that punishing tone—now known as both the “Gothenburg sound” for the Swedish city’s high metal density, and the “chainsaw sound” for obvious reasons—and fans were eager to discover it. Over the course of little over two minutes, Ekeroth explained the secret: a Boss HM-2 with every knob turned all the way up. That’s all. Chainsaw city.

As one might expect, prices quickly exploded and haven’t calmed down since. But what’s so special about a distortion pedal with just volume, distortion and a two-band tone stack?

The big secret to the HM-2’s signature sound lies in subcircuits called gyrators. In old studio gear (and new, very expensive studio gear), audio engineers used what’s called LRC filters, heavily reliant on a component called an inductor. This component consists of a wire wrapped around some type of core, and circuits of yore used them in many things. As inductors were used much more back then, getting them custom-wound by a stateside component manufacturer was a simple task, and so precise windings were made to complement LRC filters, which rely on interactions between the inductor (L, because I was already used for current), a resistor (R) and a capacitor (C). These are used as powerful EQ controls.

The HM-2, by contrast, uses a “gyrator” or a transistorized simulation of an inductor, to provide super-powerful, console-style EQ circuits that boost or cut the frequency at which they are centered. The HM-2 has three such circuits—the L[ow] knob is centered at 86.79Hz, while the H[igh] knob is twice as powerful, using two simultaneous gyrators centered at 958.47Hz and 1278.6Hz. A rich harmonic distortion boosting all three of those frequency bands by 10dB is a punishing spatial filler that sounds pretty much exactly like Swedish death metal, no matter how you slice it. Our Giygas employs a similar gyrator circuit, with a much wider bandwidth and centered at 900Hz.

Boss HM-2

Some might say that the real power lies within the HM-2’s stacking ability, and they’re right, especially when one keeps the Dist[ortion] control in check, as the powerful EQ will exactingly sculpt any pedal before it. This is likely the reason that Clapton and Gilmour found such common ground with Entombed, because it was the first time that studio-style EQ controls were available in a pedal (I see you, S.Hawk Tonal Expander). And any pedal that can bring both the father and son from Twisted Sister’s “We’re Not Gonna Take It” together at the musical table is a bona fide classic, no matter what it’s named after.