Supro Big Star S6651 - Standard preset

Verified · 87/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Supro S6651, catalogued as the Big Star, is a mid-1960s two-channel Valco combo. The Standard channel has its own volume and tone; the Tremolo/Reverb channel adds a tube-driven spring reverb with level control and footswitch, and a 12AX7 tremolo with speed and intensity. A 12AX7 phase inverter drives cathode-biased 6L6s with no negative feedback on a four-diode bridge rectifier with a standby switch, into two 12-inch speakers.

• Made in: USA
• Channels: 2
• Preamp tubes: 5× 12AX7
• Power tubes: 2× 6L6

Tags: american, vintage, 6l6, reverb, tremolo, two-channel.

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.