What tubes does the THD Bivalve 1 3 061605 use?

The THD Bivalve 1 3 061605 uses 2× 12AX7 preamp tubes and 2× EL34 power tubes.

When was the THD Bivalve 1 3 061605 produced?

The THD Bivalve 1 3 061605 was produced 1995–2010.

THD Bivalve 1 3 061605 preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The THD BiValve-30 is a two-channel amp from Andy Marshall's THD Electronics, notable for its tube-switching flexibility that allows players to run EL34, 6L6, EL84, or other power tubes without rebias. This version 1.3 schematic documents the circuit design that made the BiValve a favorite among tone experimenters seeking British or American flavors from a single amp. Its innovative tube versatility and quality construction made it a boutique favorite.

Years produced: 1995–2010
Made in: USA
Wattage: 30W
Channels: 2
Preamp tubes: 2× 12AX7
Power tubes: 2× EL34

Tags: american, crunch, modern.

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.