Gibson GA-60 Hercules preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The GA-60 Hercules is a 1960s single-channel Gibson combo with two inputs and volume, bass and treble controls. Its photocell (LDR) is not a tremolo: a rectified sample of the speaker output, set by a factory trim, lights the cell to compress the signal when played loud. A 6EU7 gives gain and a split-load inverter, a second 6EU7 drives a fixed-bias push-pull pair of 7591s, and a GZ34 rectifies. Its circuit is very close to the GA-65 Rivoli.

• Made in: USA
• Wattage: 25W
• Channels: 1
• Preamp tubes: 2× 6EU7
• Power tubes: 2× 7591

Tags: american, vintage, clean, tremolo.

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.