National Horizon 20 preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

A 20-watt hi-fi power amplifier, not a guitar amp. One 12AX7 serves as the audio amplifier and phase inverter, driving two 6L6Gs with a 5U4G rectifier. It has inputs for TV, phono, tape and tuner and a gain control, and it is a popular conversion candidate because of its 6L6 output stage.

• Made in: USA
• Wattage: 20W
• Channels: 1
• Preamp tubes: 1× 12AX7
• Power tubes: 2× 6L6G

Tags: american, vintage, 6l6, power-amp.

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.