What tubes does the Marshall Jmp Organ 50W 1989U use?

The Marshall Jmp Organ 50W 1989U uses 3× ECC83 (12AX7) preamp tubes and 2× EL34 power tubes.

When was the Marshall Jmp Organ 50W 1989U produced?

The Marshall Jmp Organ 50W 1989U was produced 1966–1975.

Marshall Jmp Organ 50W 1989U preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Marshall 1989 Super Organ 50W was a specialized variant of the JMP 50W chassis voiced specifically for electronic organs and keyboards. Its frequency response is shaped to reproduce the full-range character of organ tonewheels and early synthesizers rather than guitar, with a flatter midrange curve and extended high-frequency response. Despite its intended use case, the Super Organ's relatively clean headroom and warm EL34 power section attracted adventurous guitarists and keyboard players who wanted a distinctive voice separate from the standard Super Lead or Super Bass.

Years produced: 1966–1975
Made in: UK
Wattage: 50W
Channels: 2
Preamp tubes: 3× ECC83 (12AX7)
Power tubes: 2× EL34

Tags: british, vintage, 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.