What tubes does the Marshall JMP 2204 (6550) use?

The Marshall JMP 2204 (6550) uses 3× ECC83 preamp tubes and 2× 6550 power tubes.

When was the Marshall JMP 2204 (6550) produced?

The Marshall JMP 2204 (6550) was produced 1975–1981.

Marshall JMP 2204 (6550) preset

Verified · 93/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The JMP 2204 is the 50-watt master-volume head introduced alongside the 2203 in 1975; this is the 1976 US-market version. High and Low inputs feed cascaded ECC83 stages with a preamp Volume, a cathode follower drives Treble, Middle and Bass, and a Master follows the tone stack so the preamp can overdrive at lower volume. An ECC83 long-tail inverter with Presence drives two 6550s. It became the basis for the JCM800 2204.

Years produced: 1975–1981
Made in: UK
Wattage: 50W
Channels: 1
Preamp tubes: 3× ECC83
Power tubes: 2× 6550

Tags: british, vintage, crunch, high-gain, el34, mid-wattage.

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.