Ampeg SVT - Main preset

Close · 72/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The SVT Rev A is the earliest documented revision of the world's most iconic bass amplifier. The Main channel feeds the full 300-watt circuit — the most powerful production bass amp ever made at the time of its introduction. Rev A represents the foundational circuit from which all subsequent SVT variants were developed.

• Years produced: 1969–present
• Made in: USA
• Wattage: 300W
• Channels: 2
• Preamp tubes: 6× 12AX7, 2× 12AU7
• Power tubes: 6× 6550

Known for: Paul McCartney, Geddy Lee, John Entwistle, Lemmy Kilmister, Geezer Butler, Cliff Burton.

Heard on: Won't Get Fooled Again — The Who (1971); Whole Lotta Love — Led Zeppelin (1969); Tom Sawyer — Rush (1981).

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

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.