Airline GDR-8518A preset

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

The Airline GDR-8518A is a large Montgomery Ward tube amp with two input channels of three jacks each, one on each half of the first 12AX7, and each with its own Bass, Treble and Volume. A second 12AX7 mixes and splits the signal into a 6SN7 push-pull driver, which feeds four 6V6GTs in parallel push-pull into a bank of 3.2-ohm speakers. A 6AU6 oscillator gives vibrato with Speed, Strength and a footswitch, and a 5Y3GT rectifies the supply.

• Made in: USA
• Wattage: 30W
• Channels: 1
• Preamp tubes: 2× 12AX7, 1× 6SN7, 1× 6AU6
• Power tubes: 4× 6V6GT

Tags: american, vintage, 6v6, vibrato.

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.