Harmony H-304A preset

verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The H-304A is a revision of the H-304 that swaps the 6BF6 pentode preamp for a 6C4 triode, followed by a 6AT6 driver and a single-ended 6V6 with 5Y3 rectifier. It has three inputs, one volume and one tone control, and a 10-inch speaker, for about 5 watts. The result is a simple, warm small amp that saturates early.

• Made in: USA
• Wattage: 5W
• Channels: 1
• Preamp tubes: 1× 6C4, 1× 6AT6
• Power tubes: 1× 6V6

Tags: american, vintage, practice, low-wattage, 6v6, breakup.

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.