Hammond AO-39 preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The AO-39 is the built-in power amplifier from Hammond's A-100 series console organs. A 12AX7 serves as the input stage and phase inverter, driving a push-pull pair of 6BQ5 (EL84) output tubes with a 5U4GB rectifier. Its simple, clean EL84 power stage makes it a popular chassis for conversion into a guitar or harp amp.

• Made in: USA
• Wattage: 15W
• Channels: 1
• Preamp tubes: 1× 12AX7
• Power tubes: 2× 6BQ5

Tags: american, vintage, power-amp, el84, 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.