What tubes does the Marshall JCM1 use?

The Marshall JCM1 uses 2× 12AX7 preamp tubes and 1× 12AU7 power tubes.

When was the Marshall JCM1 produced?

The Marshall JCM1 was produced 2012.

Marshall JCM1 preset

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

The JCM1 is part of Marshall's 2012 50th Anniversary set of 1-watt heads, voiced after the JCM800. A 12AX7 input stage with Pre-amp gain feeds a second stage with switchable LED/diode clipping (a mode switch, not a second channel), then a 12AX7 stage and MOSFET follower into Treble, Middle and Bass and a Master Volume. A 12AX7 phase inverter drives a push-pull 12AU7 output, switchable between 1 and 0.1 watt.

Years produced: 2012
Wattage: 1W
Channels: 1
Preamp tubes: 2× 12AX7
Power tubes: 1× 12AU7

Tags: british, modern, crunch, high-gain, low-wattage, practice.

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.