Sunn Coliseum PA preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Sunn Coliseum PA is a 1967 tube PA head with four microphone channels on identical 12AX7 halves, each with its own volume control. They sum into shared tone stages, a 6AN8 and four KT88 output tubes. It is a high-powered, clean American tube head.

• Made in: USA
• Wattage: 120W
• Channels: 1
• Preamp tubes: 3× 12AX7, 1× 6AN8
• Power tubes: 4× KT88

Tags: american, vintage, kt88, clean, high-wattage.

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.