Ampeg SVT-400T preset

Verified · 84/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg SVT-400T is a solid-state bass head from 1988 with one preamp and a two-channel (stereo) power amp. Inputs at 0 and -15 dB feed gain and a Sustain compressor, then low, mid and high controls with pull switches for Ultra Low, Ultra High and the graphic EQ, a Mid Shift control, and a seven-band graphic EQ that can also be switched by footswitch. A stage volume with pull limit defeat, bi-amp frequency and balance, an effects loop and balanced line out complete it.

Tags: american, bass, solid-state, stereo, 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.