What tubes does the Harmony H-306A use?

The Harmony H-306A uses 12AX7 preamp tubes and 6L6 power tubes.

When was the Harmony H-306A produced?

The Harmony H-306A was produced 1964–1968.

Harmony H-306A preset

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

The Harmony H306A is a revised version of the H306 with updated components, maintaining the same push-pull circuit architecture and feature set. Harmony's revision practice was common across its amplifier line, with A-suffix models reflecting incremental engineering changes rather than fundamental redesigns. The H306A shares the H306's full, warm clean character.

Years produced: 1964–1968
Made in: USA
Wattage: 14W
Channels: 2
Preamp tubes: 12AX7
Power tubes: 6L6

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.