Ampeg SVT (1972) - Channel 2 preset

Verified · 93/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 1972 SVT with 6550A output tubes is the definitive version of Ampeg's flagship bass head. Channel 2 provides a slightly brighter input path into the same massive 300W power section. Natural compression from the six-tube power stage delivers the thunderous, punchy low-end that defined stadium-level bass tone for over five decades.

• 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: YYZ — Rush (1981); Iron Man — Black Sabbath (1970).

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.