Marshall Jmp Mastervol 100W 2203U preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Marshall 2203 Master Volume 100W is the direct predecessor of the JCM800 2203 and represents Marshall's first widely successful implementation of a master volume control. By adding a post-phase-inverter master volume to the single-channel Super Lead circuit, players could push the preamp into saturation without requiring the full output of a quad EL34 power section. The result was the first Marshall head to offer truly usable high-gain tones at moderate stage volumes, laying the template for virtually every high-gain British amplifier that followed.

• Years produced: 1975–1981
• Made in: UK
• Wattage: 100W
• Channels: 1
• Preamp tubes: 3× ECC83 (12AX7)
• Power tubes: 4× EL34

Known for: Zakk Wylde, Dave Murray.

Tags: british, vintage, crunch.

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.