Marshall JCM800 Lead Series 50W & 100W 1959A preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Marshall JMP Super Lead is the amp that defined the sound of rock — its aggressive, midrange-heavy roar powered stages from Woodstock to stadium tours for over a decade. Played cranked into a full 4×12 stack, it produces that unmistakable plexi crunch: raw, dynamic, and richly harmonic. Its two high- and low-sensitivity inputs can be jumpered together for even more gain, a trick favored by countless classic rock players.

Known for: Jimi Hendrix, Jimmy Page, Pete Townshend, Eric Clapton, Eddie Van Halen, Angus Young.

Heard on: All Along the Watchtower — Jimi Hendrix (1968); Whole Lotta Love — Led Zeppelin (1969); Won't Get Fooled Again — The Who (1971).

Tags: british, vintage, plexi, crunch, classic-rock, high-headroom.

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.