Gibson BR-9 preset

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

The BR-9 is a small post-war Gibson amplifier, typically paired with lap steels, with two instrument inputs and a single volume control. Both inputs mix into one half of a 6SN7, then the volume and the second 6SN7 half drive an interstage transformer that splits the phase for a cathode-biased push-pull pair of 6V6GTs. A 5Y3 rectifier with the speaker field coil as its filter choke powers it. There is no tone control and no feedback.

Tags: american, vintage, clean, 6v6.

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.