Gibson GA-30 (6SJ7 Preamp) - Channel I preset

Close · 78/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The Gibson GA-30 with 6SJ7/65J7 preamp was an early 1950s version of Gibson's popular GA-30 combo, using older pentode preamp tubes before the transition to 12AX7s. It produced warm, rounded tones characteristic of early postwar American amp design.

• Years produced: 1950–1955
• Made in: US
• Wattage: 14W
• Channels: 2
• Preamp tubes: 1× 65J7
• Power tubes: 2× 6L6

Tags: american, vintage, 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.