What tubes does the THD Univalve 1 4 use?

The THD Univalve 1 4 uses 1× 12AX7 preamp tubes and 1× EL34 power tubes.

When was the THD Univalve 1 4 produced?

The THD Univalve 1 4 was produced 1999–2010.

THD Univalve 1 4 preset

Close · 60/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The THD UniValve version 1.4 schematic documents Andy Marshall's refined single-channel boutique amp, renowned for accepting multiple power tube types without rebiasing. The UniValve produces approximately 15 watts in single-ended class A operation, delivering exceptional touch sensitivity and harmonic complexity. It has been a long-running favorite among recording guitarists and boutique amp enthusiasts.

Years produced: 1999–2010
Made in: USA
Wattage: 15W
Channels: 1
Preamp tubes: 1× 12AX7
Power tubes: 1× 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.