What tubes does the Ampeg M-12-A (7591 version) - Instrument use?

The Ampeg M-12-A (7591 version) - Instrument uses 2× 12AX7 preamp tubes and 2× 7591A power tubes.

When was the Ampeg M-12-A (7591 version) - Instrument produced?

The Ampeg M-12-A (7591 version) - Instrument was produced 1962–1966.

Ampeg M-12-A (7591 version) - Instrument preset

Verified · 83/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg M-12 Mercury with 7591A output tubes represents a higher-powered variant of the Mercury series guitar combo. The 7591A pentode output tube was favored by Ampeg during the 1960s for its combination of power and tonal character — providing more output than a pair of 6V6 tubes while maintaining a clean, warm American sound. This version of the M-12 offered noticeably more headroom for players who needed to stay clean at higher volumes.

Years produced: 1962–1966
Made in: USA
Wattage: 22W
Channels: 2
Preamp tubes: 2× 12AX7
Power tubes: 2× 7591A

Tags: american, vintage, 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.