What tubes does the Supro S6420TR (1965 Thunderbolt) - Main use?

The Supro S6420TR (1965 Thunderbolt) - Main uses 3x 12AX7 preamp tubes and 1x 6550 power tubes.

When was the Supro S6420TR (1965 Thunderbolt) - Main produced?

The Supro S6420TR (1965 Thunderbolt) - Main was produced 1963–1968.

Supro S6420TR (1965 Thunderbolt) - Main preset

Verified · 84/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Supro S6420TR is the tremolo-equipped version of the 6420 series, adding a bias-vary tremolo effect to the Thunderbolt's base circuit. The tremolo is a smooth, hypnotic pulse that pairs beautifully with the amp's naturally compressed tone. Like the standard 6420, the S6420TR is a highly desirable collector's piece among boutique amp enthusiasts and blues players.

Years produced: 1963–1968
Made in: USA
Wattage: 35W
Channels: 1
Preamp tubes: 3x 12AX7
Power tubes: 1x 6550

Tags: american.

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.