What tubes does the Supro Thunderbolt S6420 (SS) - Normal use?

The Supro Thunderbolt S6420 (SS) - Normal uses 2× 12AX7 preamp tubes and 2× 6L6 power tubes.

When was the Supro Thunderbolt S6420 (SS) - Normal produced?

The Supro Thunderbolt S6420 (SS) - Normal was produced 1965–1968.

Supro Thunderbolt S6420 (SS) - Normal preset

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

The Supro Thunderbolt S6420 with solid-state rectifier is a mid-to-late 1960s variant of the Thunderbolt series, using silicon diodes for rectification rather than the tube rectifier found in earlier models. The solid-state rectifier provides tighter, more immediate response and slightly more aggressive attack compared to the tube rectifier version. Both variants share the fundamental Thunderbolt character but respond differently under dynamic playing.

Years produced: 1965–1968
Made in: USA
Wattage: 35W
Channels: 2
Preamp tubes: 2× 12AX7
Power tubes: 2× 6L6

Tags: american, vintage, crunch.

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.