Gibson GA-75W - Channel 1 preset

Verified · 82/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The GA-75W is an early-1950s Gibson combo laid out like the earlier GA-75: a single-input channel on a 6SJ7 pentode and a four-input channel on a pair of 6SC7 twin triodes, each with its own volume, mixed into shared tone controls. A 12AX7 replaces the earlier 6SC7 as the phase inverter, driving a push-pull pair of 6L6GA output tubes on a 5V4G rectifier into one speaker.

• Made in: USA
• Wattage: 25W
• Channels: 2
• Preamp tubes: 1× 6SJ7, 2× 6SC7, 1× 12AX7
• Power tubes: 2× 6L6GA

Tags: american, vintage, clean, 6l6.

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.