Distortion
Intensity of the heavy, chainsaw-like grind.
- Turn up More aggressive saturation and compression.
- Turn down Less extreme; more of the guitar’s dynamics come through.
Pedals / HM-2 heavy metal
Buzz Saw
HM-2 heavy metal · play-tested
seth — fish
seth@ninevolt:~$
Knobs
In the TUI each knob runs from low (left / 0%) to high (right / 100%). Start near noon, then nudge while you play.
Color
Shapes the mid/high character of the buzz.
- Turn up Often brighter or more scooped depending on the preset feel — expect a more cutting top.
- Turn down Darker, thicker grind.
Level
Output volume.
- Turn up Louder.
- Turn down Quieter.
Inspired by
Boss HM-2 Heavy Metal (1983–1991, Waza Craft HM-2W reissue) — the “Swedish chainsaw” pedal. Entombed Left Hand Path, Bolt Thrower, early Swedish death metal. Distortion, Color (Low/High gyrator EQ collapsed to one knob), Level.
Signal path
| Step | What it does |
|---|---|
| High-pass ~80 Hz | Input coupling / sub trim. |
| Distortion gain | Distortion knob → up to ~96× (1 + distortion^1.02 × 95). |
| Soft asym feedback clip | OD-1-class diodes in op-amp feedback — first saturation stage. |
| Ge crossover distortion | Series germanium pair squares zero crossings (“chainsaw” artifact). |
| Hard silicon clip | DS-1-class hard clip to ground — final limiting. |
| Low gyrator ~87 Hz | Color boosts sub/low punch (L knob center). |
| High gyrators ~958 / ~1278 Hz | Color boosts upper-mid bite (H knob dual peaks). |
| Mid scoop + Color blend | Distortion deepens mid cut; Color tilts low/high mix. |
| Level + clamp | Level output trim (0.12 + level × 1.15). |
How we modeled it
HM-2 path: gain → cascaded clip → gyrator L/H crossover EQ → mid scoop. Color maps both Low and High gyrator boosts; Distortion drives clip depth and scoop. Sunlight Studio preset targets all-knobs-hot chainsaw grind.
Simplifications
- Dual Color knobs (L/H) merged into one Color - Gyrators approximated as crossover filters, not transistor inductor sims - Single gain stage vs three op-amp blocks on schematic