Gibson GA-75 (Later) - Channel II preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

This later GA-75 is a 1960s two-channel Gibson combo, two inputs per channel, each channel with its own loudness, bass and treble controls. Two 6EU7s handle the channel gain stages, a 6C4 adds gain, and a 6FQ7 long-tail phase inverter drives a fixed-bias push-pull pair of 6L6GC tubes on a solid-state rectifier, with a monitor jack. The drawing shows a 15-inch speaker for the GA-75L and two 10-inch speakers for the GA-75.

• Made in: USA
• Wattage: 30W
• Channels: 2
• Preamp tubes: 2× 6EU7, 1× 6C4, 1× 6FQ7
• Power tubes: 2× 6L6GC

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.