Leslie 51 / 51C - Flutes preset

Verified · 85/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Leslie 51/51C is a two-channel power amplifier for Leslie organ speaker cabinets: one section feeds the rotating speakers with flute and pedal tones, the other a fixed set of speakers for the string voices. It is an organ amp, not a guitar amp. Each section has its own volume and a 12AU7 driver, into a push-pull pair of 6550s (KT88s allowed) and a pair of 6973s, with an OC3 regulator. Early units use a 5V3 rectifier, later ones solid-state.

• Made in: USA
• Channels: 2
• Preamp tubes: 2× 12AU7
• Power tubes: 2× 6550, 2× 6973

Tags: american, vintage, 6550, 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.