What tubes does the Marshall JCM900 Dual Reverb 4500 - Channel B use?

The Marshall JCM900 Dual Reverb 4500 - Channel B uses 3× ECC83 preamp tubes and 2× EL34 power tubes.

When was the Marshall JCM900 Dual Reverb 4500 - Channel B produced?

The Marshall JCM900 Dual Reverb 4500 - Channel B was produced 1990–2000.

Marshall JCM900 Dual Reverb 4500 - Channel B preset

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

The JCM900 4500 Dual Reverb is the 50-watt version of the 4100, launched in 1990. A Normal channel and a diode-clipped Boost channel, each with its own gain and pre-EQ, share a Master EQ, reverb with a separate level for each channel, an effects loop and footswitchable A/B master volumes. Three ECC83s and op-amp stages make up the preamp; an ECC83 inverter drives two EL34s (5881s on later issues), with a power switch.

Years produced: 1990–2000
Made in: UK
Wattage: 50W
Channels: 2
Preamp tubes: 3× ECC83
Power tubes: 2× EL34

Tags: british, crunch, high-gain, reverb, 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.