Fender Bassman AA270 - Normal preset

Verified · 82/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The AA270 is a silverface Bassman head from around 1970. The Bass Instrument channel has two inputs, treble, bass, volume and a Deep switch; the Normal channel has two inputs, treble, bass, volume and a bright switch. Both channels mix into a further 7025 gain stage, and a 12AT7 long-tail inverter drives two fixed-bias 6L6GCs from a silicon diode rectifier into a 4-ohm load. It gives clean, punchy tone for bass, and guitarists often use it as a clean platform.

Tags: american, vintage, silverface, bass, 6l6, clean.

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.