Mesa Boogie Mark IV preset

Verified · 93/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Mark IV has three channels (Rhythm 1, Rhythm 2 and Lead) with extensive voicing switches, the 5-band graphic EQ and Simul-Class power. It was John Petrucci's main amp through much of the 1990s.

• Years produced: 1990–2008
• Made in: USA
• Wattage: 85W
• Channels: 3
• Preamp tubes: 5× 12AX7
• Power tubes: 4× 6L6

Known for: John Petrucci, Mark Morton, Willie Adler.

Heard on: Ghost Walking — Lamb of God (2012).

Tags: american, high-gain, crunch, 6l6, high-wattage, multi-channel.

Schematic-derived preset files for 16 Fractal and Line 6 modelers: Axe-Fx II/XL/XL+, Axe-Fx III, FM3, FM9, and the full Helix family (Floor, LT, Rack, HX Stomp, HX Stomp XL, Native).

Gridleak extracts amp parameters from original circuit schematics using AI vision — component values, gain staging, tone stack topology, tube types — then generates native preset files for every supported modeler. Every extraction is scored 0–100 and the score is published.