Ampeg SVT (HD / Original SVT) - Channel 1 preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The original SVT HD (Head) is the first version of what became the world's most iconic bass amplifier. Introduced in 1969, it delivered an unprecedented 300 watts of tube power, transforming live bass reinforcement forever. The Channel 1 input feeds directly into an ultra-high-gain preamp before the massive six-tube power section.

• Years produced: 1969–1972
• 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); Ramble On — Led Zeppelin (1969).

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.