Fortin Cali Mod (100 W Marshall) preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Cali Mod is Mike Fortin's high-gain modification of a 100-watt Marshall, the forerunner of his later Cali head. Two cascaded gain controls with bright switches and a Bold/Spongy switch feed a third 12AX7 stage, a transistor clipper and a cathode follower into a post-gain tone stack. Presence, Resonance and Hair/Thump switches shape the power section, where four EL34s run at about 480 volts.

• Wattage: 100W
• Channels: 1
• Preamp tubes: 3× 12AX7
• Power tubes: 4× EL34

Tags: boutique, modern, high-gain, metal, el34, high-wattage.

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.