Muzak 920D preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 920D is a Muzak background-music valve amplifier, a PA amp rather than a guitar amp. The music line input has a gain-limit control plus bass and treble into a 6SJ7 stage with its own Muzak volume, and a microphone input has its own 6SJ7 and Micro volume, with a relay to let the mic override the music. A 6SJ7 gain stage and a 6SJ7 phase inverter drive a push-pull pair of 6L6s from a 5U4 rectifier, for 23 watts into multi-tap line outputs.

Tags: american, vintage, 6l6, mid-wattage, clean.

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.