Airline GDR-8513A - Microphone preset

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

The Airline GDR-8513A is a two-channel Montgomery Ward tube amp with two Instruments inputs and a Microphone input, each channel with its own Volume. The instrument channel adds a Bass control, and a shared Tone control follows. A 6AU6 pentode gain stage feeds a second 6AU6 working as a split-load phase inverter, driving two cathode-biased 6V6GTs into a 3.2-ohm speaker, with a 6X5GT rectifier and no overall feedback drawn.

Tags: american, vintage, 6v6, two-channel, low-wattage.

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.