FBT S.B.250 / S.B.125 preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The FBT S.B.250 and S.B.125 are solid-state bass amps in two power versions. The preamp uses transistors and op-amps with gain, bright, treble/middle/bass and a six-band graphic EQ, plus slave in/out. Each version has its own transistor power unit.

• Made in: Italy
• Wattage: 250W
• Channels: 1

Tags: italian, solid-state, bass, 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.