St. George Guitar Amplifier preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The St. George tube amp is a tiny AC/DC practice amplifier with no power transformer and a hot chassis. Two instrument inputs feed the triode of a 12AV6 (a 12AT6 can be used for a little less gain), then a single Volume control drives one cathode-biased 50C5 beam tetrode single-ended into the speaker. A 35W4 half-wave rectifier supplies the high voltage. The only controls are the power switch and Volume.

• Wattage: 2W
• Channels: 1
• Preamp tubes: 1× 12AV6
• Power tubes: 1× 50C5

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.