Marshall Jcm900 25Xx 45Xx 50W preset

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

The JCM900 50-watt models (2500 SL-X and 4500 Dual Reverb series) deliver the JCM900 platform at reduced power, using two EL34s to produce a more compressed and harmonically rich output stage response than the 100-watt versions. Players who recorded extensively through the 1990s often preferred the 50-watt JCM900s for studio work, finding that the smaller output stage responded more naturally to dynamic playing. The SL-X 50-watt in particular was prized for heavy recording applications where the tighter compression of a two-EL34 output stage was beneficial.

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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.