Marshall JMP 1987 Lead 50 - High Treble preset

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

The Marshall 1987 Lead 50 is the 50-watt sibling of the Super Lead 1959, with four inputs across two channels, three ECC83s, bright caps, and a pair of EL34s on a solid-state rectifier, with no master volume. It breaks up earlier than the 100-watt head, with a slightly softer, more touch-sensitive plexi crunch.

• Years produced: 1969–1981
• Made in: UK
• Wattage: 50W
• Channels: 2
• Preamp tubes: 3× ECC83
• Power tubes: 2× EL34

Known for: Michael Schenker.

Heard on: Only You Can Rock Me — UFO (1978).

Tags: british, vintage, plexi, el34, mid-wattage, two-channel, 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.