Marshall JMP Organ 1989 - High Treble preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 1989 is the 50-watt organ model of the plexi-era range; this 1970 Unicord drawing shows a standard plexi-type circuit. Two input channels feed an ECC83 gain stage and cathode follower into the treble/bass/middle stack, with an ECC83 long-tail phase inverter driving two EL34s and a half-power switch.

• Made in: UK
• Wattage: 50W
• Channels: 2
• Preamp tubes: 3× ECC83
• Power tubes: 2× EL34

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