Ampeg Jet J-12 preset

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

The Ampeg Jet J-12 is a single-channel tube guitar combo of the late 1960s with bright and normal inputs into half a 12AX7, then a volume and a single tone control. The other half of that 12AX7 runs a photocell tremolo with speed and a footswitch. A second 12AX7 provides another gain stage and a split-load phase inverter for a cathode-biased push-pull pair of 7591s, with feedback from the speaker and a solid-state bridge rectifier.

• Made in: USA
• Wattage: 12W
• Channels: 1
• Preamp tubes: 2× 12AX7
• Power tubes: 2× 7591

Tags: american, vintage, tremolo, low-wattage.

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.