Marshall Super PA 1963 preset

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

The Marshall 1963 Super PA is a 50-watt valve PA head (the number is the model code, not the year); this drawing is dated July 1970. Four channels, each with a pair of inputs and its own volume, run through two ECC83s, then mix into a third ECC83 recovery stage feeding a shared treble, middle and bass stack with presence. An ECC83 long-tail phase inverter drives a pair of EL34s with a 4, 8 or 16-ohm output.

Tags: british, vintage, el34, mid-wattage, clean.

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.