What tubes does the Ampeg J-12T - Guitar use?

The Ampeg J-12T - Guitar uses 3× 12AX7 preamp tubes and 2× 7591A power tubes.

When was the Ampeg J-12T - Guitar produced?

The Ampeg J-12T - Guitar was produced 1963–1966.

Ampeg J-12T - Guitar preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The J-12T is a guitar-specific Jet series combo with 7591A output tubes. The Guitar channel is voiced specifically for electric guitar with an EQ curve optimized for midrange clarity and note definition. The J-12T's 7591A tubes produce a warm, slightly compressed tone with good harmonic complexity.

Years produced: 1963–1966
Made in: USA
Wattage: 18W
Channels: 2
Preamp tubes: 3× 12AX7
Power tubes: 2× 7591A

Tags: guitar, american, vintage, low-wattage, clean.

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.