Ampeg SVT-III preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg SVT-III is a hybrid bass head. Its preamp runs on three 12AX7s with bright and normal inputs, Ultra Low and Ultra High switches, bass, treble and a mid control with a five-position frequency switch on a tapped inductor, a pull switch for the limiter, and a slider graphic EQ. The power amp is solid-state: an op-amp front end with an optical limiter drives four pairs of MJ15022/MJ15023 bipolar output transistors, with relay speaker protection and thermal shutdown.

• Made in: USA
• Channels: 1
• Preamp tubes: 3× 12AX7

Tags: american, bass, hybrid.

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.