Ampeg SJ-12T preset

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

The Ampeg SJ-12T is a 1990s tube guitar combo with separate guitar and accordion inputs. One 9-pin dual triode supplies a gain stage with volume and tone controls and the tremolo oscillator, with speed and intensity. A second dual triode is the long-tail phase inverter for a fixed-bias pair of octal output valves with a bias trim. Spring reverb is driven and recovered by a TL072 op-amp, and both reverb and tremolo switch from a footswitch.

• Channels: 1

Tags: american, reverb, 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.