What tubes does the Supro S6688 - Standard Channel use?

The Supro S6688 - Standard Channel uses 2× 12AX7 preamp tubes and 2× 6973 power tubes.

When was the Supro S6688 - Standard Channel produced?

The Supro S6688 - Standard Channel was produced 1962–1968.

Supro S6688 - Standard Channel preset

Verified · 82/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Supro S6688 is a higher-powered model in the Valco Supro range, delivering 25 watts with the characteristic American brightness and raw harmonic texture the brand is known for. The dual-channel configuration provided players with clean and boosted options, while the 6973 power tubes contribute a unique tonal signature that differs from more conventional output tube choices. This model sits near the top of the Supro vintage lineup in terms of power and features.

Years produced: 1962–1968
Made in: USA
Wattage: 25W
Channels: 2
Preamp tubes: 2× 12AX7
Power tubes: 2× 6973

Tags: american, vintage.

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.