Gibson GA-20 (12AY7) - Microphone preset

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

This version of the GA-20 is a two-channel Gibson combo. A Mic channel and an Instruments channel each have two inputs on their own 12AY7, both halves in parallel, and their own volume control, sharing one tone control. A 12AX7 long-tail phase inverter then drives a push-pull pair of 6V6GTs on a 5Y3 rectifier.

Tags: american, vintage, clean, 6v6, low-wattage, two-channel.

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.