Ampeg SVT-II preset

Verified · 89/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg SVT-II is a 300-watt all-tube bass head from the early 1990s. Bright and normal inputs feed a three-tube preamp with volume, Ultra Low and Ultra High switches, bass, treble and a midrange control with a five-position frequency switch on a tapped inductor, plus a footswitchable graphic EQ and a balanced output. In the power amp a 12AX7 phase inverter with a balance trim drives two 12AU7 drivers, each with its own bias control, for six 6550s.

• Made in: USA
• Wattage: 300W
• Channels: 1
• Preamp tubes: 4× 12AX7, 2× 12AU7
• Power tubes: 6× 6550

Tags: american, bass, 6550, high-wattage.

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.