Marshall JCM800 4010 preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The JCM800 4010 is the 1x12 combo version of the 50-watt single-channel master-volume JCM800, sharing the 2204 head's circuit. High and Low inputs feed cascaded ECC83 stages behind a bright-capped Preamp Volume, a cathode follower drives Treble, Middle and Bass, and a Master Volume follows. An ECC83 long-tail inverter with Presence drives two EL34s off a choke-filtered silicon supply, with a DI output.

Tags: british, crunch, high-gain, el34, mid-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.