DOD FX56 American Metal

The DOD FX56 American Metal is a high-gain distortion pedal released in 1984¹². It is a small chapter in a larger story: the same circuit appeared twice in DOD and DigiTech gear. Electric Druid's analysis of the DigiTech PDS-1550 found that the PDS-1550's Metal Distortion channel is practically identical to the Boss HM-2 circuit, and that "It turns out Digitech didn't do this once but twice, the DOD FX56 'American Metal' pedal is the same circuit again"³. So the FX56 is, in effect, a compact pedal carrying the PDS-1550's metal channel.

What it does and how it relates to the Boss HM-2

The Boss HM-2 Heavy Metal, produced from 1981 to 1987 in Japan, is the pedal this circuit family is measured against. TONEHOME calls it "the cornerstone of the Swedish death-metal 'buzzsaw' guitar sound, sporting tons of gain," with a Color Mix control that can boost or cut mids⁴. Guitar.com notes the original HM-2, "endearingly referred to as the Swedish Chainsaw," is most associated with Swedish death metal⁵. Boss discontinued the model in 1993, replacing it with the MT-2 Metal Zone, which offers a similar midrange control⁴.

Against that background, Aion FX's take on the FX56 is the clearest comparison: "the American Metal has almost the exact same circuit layout, just with different parts values and with the two tone knobs combined into one"¹². The knob count tells the story: a commenter comparing the two circuits on the Tagboard Effects page put it as "3 knob vs 4 knobs"². Aion FX also cautions that "the pedals don't really sound the same"¹, and the Tagboard Effects author noted the circuit "has some similarities with Boss HM-2 Heavy Metal as the youtube demo below suggests"².

For sound, the site's own descriptions stay attributed: the Tagboard Effects author, who built the layout, wrote simply that it "Sounds pretty mean"².

The FX56B variant

DOD also made an FX56B Super American Metal. According to the Tagboard Effects author, it differs by having Bass and a Presence control instead of a tone knob. He had not seen a schematic for the FX56B, but suggested that "tweaking the low gyrator to have a control should be doable" for builders who want to move the FX56 layout in that direction².

Building the FX56

The pedal has a following among DIY builders, and the published vero layout comes with practical notes²:

• The stripboard layout measures 21x29²
• A 1590B enclosure is possible for very compact builds, but a 125B or 1590BB is recommended for most builders²
• One correction: the box capacitor labeled 47uF near Q1 should be 47nF, which the author confirmed and said he would fix²
• Difficulty is rated similar to a Triple Wreck, with the FX56 much cheaper second hand²
• A builder in the Philippines verified the layout, calling it "very very good sounding" and confirming the circuit schematic is correct²

Buying one used

The Tagboard Effects author paid €25 for his unit in September 2014 and said "they're dirty cheap on second hand market"². A commenter on the same page mentioned 40€, so the two accounts disagree; both are given here as stated. He also observed that these pedals "Seems these are more common in europe than they are in US"², which is worth knowing for players hunting one on either side of the Atlantic.

For players interested in DOD's wider distortion range, the company's catalog includes the DOD Grunge, the DOD Gunslinger Mosfet Distortion and the DOD FX33 Buzz Box, all covered on the Distortion Pedals type page.

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