Muzak 908D - Music preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 908D is a Muzak background-music valve amplifier, a PA amp rather than a guitar amp. The music line input has a gain-limiting control plus bass and treble into a 6SJ7 stage with its own Muzak volume; a separate microphone input has its own 6SJ7 and Micro volume. They mix into a 6SJ7 gain stage and a 6SJ7 phase inverter driving a push-pull pair of 6V6s with feedback, from a 5Y3 rectifier, for about 8 watts with 4-ohm and 150-ohm line outputs.

Tags: american, vintage, 6v6, clean, low-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.