Marshall 18 Watt - Tremolo preset

Verified · 91/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 18-watt Marshall is a mid-1960s EL84 combo, very different from the larger JTM heads. Normal and Tremolo channels each have Lo and Hi inputs and their own Volume and Tone; the Tremolo channel adds Speed and Intensity with a footswitch. Three ECC83s cover the preamps, oscillator and inverter, driving two cathode-biased EL84s off an EZ81 rectifier for early, touch-sensitive breakup. Boutique and DIY builders now widely copy it.

• Years produced: 1966–1968
• Made in: UK
• Wattage: 18W
• Channels: 2
• Preamp tubes: 3× ECC83
• Power tubes: 2× EL84

Known for: Billy Gibbons.

Heard on: Missin' Yo' Kissin' — Billy F Gibbons (2018).

Tags: british, vintage, el84, breakup, tremolo, low-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.