The Exar MT-1 Metal is a distortion pedal from Exar, a maker whose compact pedals also include the Exar DS-02 Distortion, the Exar HR-03 Hammer and the Exar MM-04 Moon Metal. It sits in the heavy distortion camp: when the circuit was traced and published, it was tagged as a distortion, and the tracer described its territory as HM-2 style sounds, the family of mid-heavy metal distortions associated with Boss's HM-21.
What it does
The MT-1 shapes its distortion with Hi/Lo gyrator controls. Gyrator EQ uses active circuitry to behave like a big inductor, which lets a small pedal produce the kind of swept, voiced tone shaping that a passive tone knob cannot. The tracer of the circuit, writing on the Guitar FX Layouts blog, judged them well: "Hi/Lo gyrator controls seem to be quite effective as well."1
Because the pedal's character was described by comparison, it is worth being clear about what that means for a player: HM-2 style sounds points to the aggressive, mid-pushed distortion associated with that Boss pedal, not a clean boost or a light overdrive. For other places on that spectrum, see Distortion Pedals, Overdrive Pedals and Fuzz Pedals.
The traced circuit and the DIY layout
Most of what is publicly documented about the MT-1's circuit comes from the hobbyist tracing community. A trace of the pedal had been posted on the freestompboxes.org forum for years, but it seemed to contain errors; a corrected trace was later produced by Vitalii, and on 24 November 2022 the Guitar FX Layouts blog published a stripboard (vero) layout based on it1.
The author noted that this is not a simple build. Quoting the blog: "this probably won't be the low-parts-count / easy build alternative for HM-2 style sounds." Even so, the layout fits a standard 1590B enclosure, the common Hammond-sized box used for compact DIY pedals, with "enough distorion" (sic) for the job1.
For builders, the layout leaves room for voicing changes:
- One or both clipping diode pairs can be substituted with LEDs or Schottkys1
- An on/off/on switch can be used to switch between diode pairs1
These substitutions change how hard the signal clips, which is the usual way builders tune a distortion's compression and edge1.
The published layout is a hobbyist reproduction of the circuit, not an Exar document. It is based on a trace posted on freestompboxes.org, which Vitalii corrected after errors were found in the old trace, and a commenter who built it reported it working, writing "Built a few day ago, super stoked on this!!!"1
Where the MT-1 sits among Exar's metal pedals
Exar's range covered several shades of heavy. The Exar MM-04 Moon Metal is a sibling metal distortion, and the Exar DS-02 Distortion and Exar HR-03 Hammer cover the maker's more general distortion territory. The MT-1's HM-2 style sounds description places it at the extreme end of that range1.
Videos
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Questions
What kind of pedal is the Exar MT-1 Metal?
It is a distortion pedal, tagged as such when the Guitar FX Layouts blog published a traced layout of its circuit. The author described its character as HM-2 style sounds, placing it among the heavy, mid-focused metal distortions of that family rather than a mild overdrive or a fuzz.
What do the Hi and Lo controls do?
The MT-1 uses Hi/Lo gyrator controls for its tone shaping. Gyrator controls are active EQ stages built around op-amps and capacitors rather than plain passive tone knobs. The Guitar FX Layouts author, who traced the circuit, wrote that the Hi/Lo gyrator controls seem to be quite effective.
Sources (1)
- Guitar FX Layouts: Exar MT-1 Metal, Guitar FX Layouts (tagboardeffects.blogspot.com), 2022-11-24
