Marshall JMP Lead 1987 / Super Lead 1959 - Normal preset

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

The JMP Lead heads, the 50-watt 1987 and the 100-watt 1959 Super Lead, share the plexi-era four-input, two-channel preamp with no master volume. The Bright and Normal channels each have their own volume on one ECC83, mixing into a second ECC83 gain stage and cathode follower driving Treble, Middle and Bass. An ECC83 inverter with Presence drives two EL34s in the 1987 or four in the 1959, with 6550s on US versions.

• Years produced: 1969–1981
• Made in: UK
• Wattage: 100W
• Channels: 2
• Preamp tubes: 3× ECC83
• Power tubes: 2× EL34 (1987) / 4× EL34 (1959)

Known for: Angus Young, Randy Rhoads.

Tags: british, vintage, plexi, crunch, el34, two-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.