Ampeg SJ-12R preset

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

The Ampeg SJ-12R is a 1990s all-tube reissue-series combo. A 9-pin dual triode handles the preamp, with a JFET-switched boost and a treble/mid/bass stack. A second dual triode forms a long-tail phase inverter, which drives a pair of octal output tubes. Only the spring reverb uses op-amps. It has guitar and accordion inputs.

• Made in: USA
• Channels: 1

Tags: american, reissue, reverb.

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.