Marshall 20 Watt A. Amplifier Model 1917 preset

Verified · 85/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Marshall Model 1917 is a 20W PA amplifier from the JMP era, designed for vocal reinforcement rather than guitar amplification. Its clean-voiced four-channel topology was sometimes repurposed by guitarists seeking a transparent low-power platform.

• Years produced: 1967–1973
• Made in: UK
• Wattage: 20W
• Channels: 4
• Preamp tubes: 2× ECC83
• Power tubes: 2× EL84

Tags: british, vintage, pa, low-watt.

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.