Marshall Super PA 1968 preset

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

The Marshall 1968 Super PA is a 100-watt valve PA head, shown here in its US form. Eight inputs in four pairs run into the triodes of two ECC83s, each pair with its own volume, mixed into a third ECC83 gain stage and cathode follower driving Treble, Middle and Bass. An ECC83 long-tail inverter with Presence drives four fixed-bias EL34s off a silicon bridge, so it doubles readily as a loud, clean guitar head.

Tags: british, vintage, el34, high-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.