What tubes does the Sunn 2000S use?

The Sunn 2000S uses 1× 12AX7, 1× 6AN8 preamp tubes and 4× 6550 power tubes.

Who famously used the Sunn 2000S?

Geddy Lee are among the notable players associated with the Sunn 2000S.

Sunn 2000S preset

Verified · 91/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Sunn 2000S (1969) is a bass head with four inputs into a two-stage 12AX7 preamp with bass-boost switch, a passive treble/bass stack plus contour, and a 6AN8 pentode gain stage and cathodyne inverter driving four fixed-bias 6550s from dual GZ34 rectifiers at about 510 V.

Made in: USA
Wattage: 120W
Channels: 1
Preamp tubes: 1× 12AX7, 1× 6AN8
Power tubes: 4× 6550

Known for: Geddy Lee.

Tags: american, vintage, 6550, bass, 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.