Marshall 9001 Preamp - Lead preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 9001 is a late-1980s Marshall rack preamp, a hybrid of op-amp and JFET-switched circuitry around three valve stages. The Rhythm channel has Rhythm Drive, a Voice control and two voices (R1/R2) blended by a Balance control; the Lead channel adds Lead Drive, a second drive stage, Lead Voice and its own Lead Master. Both share a five-band EQ (120 Hz to 2.5 kHz plus treble), an FX mix and Output Level, to feed a power amp such as the 9005.

Tags: british, preamp, crunch, 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.