Ampeg GU-12 preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg GU-12 is a 1969 single-channel guitar combo with bright and normal inputs into half a 12AX7, then bass, treble, volume and a tremolo intensity control. A 6U10 compactron both drives and recovers the reverb unit, with a Dimension control setting its level, and a 12DW7 adds gain and splits the phase for a cathode-biased pair of 7591As. The other half of the 12AX7 is the tremolo oscillator, using a photocell, with speed control and a footswitch.

• Made in: USA
• Wattage: 30W
• Channels: 1
• Preamp tubes: 1× 12AX7, 1× 6U10, 1× 12DW7
• Power tubes: 2× 7591A

Tags: american, vintage, 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.