Rauland PA Model 1820 preset

Verified · 84/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Rauland PA Model 1820 is a 1950 tube public-address amplifier, not a guitar amp. Two identical 6J7 pentode microphone preamps and a 6SF5 phono preamp, each with its own volume, mix into a 6SC7 audio amplifier with a tone-control network. A second 6SC7 is the phase inverter for a push-pull pair of 6L6s driving a multi-tap output transformer, powered by a 5U4G rectifier. Octal PA chassis like this are popular guitar-conversion projects.

• Made in: USA
• Channels: 1
• Preamp tubes: 2× 6J7, 2× 6SC7, 1× 6SF5
• Power tubes: 2× 6L6

Tags: american, vintage, 6l6, 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.