What tubes does the Ampeg V-4B - Channel 1 use?

The Ampeg V-4B - Channel 1 uses 2× 12AX7, 1× 6K11, 1× 12DW7, 1× 12AU7 preamp tubes and 4× 7027A power tubes.

When was the Ampeg V-4B - Channel 1 produced?

The Ampeg V-4B - Channel 1 was produced 1971–1979.

Ampeg V-4B - Channel 1 preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The V-4B is the bass version of Ampeg's 100-watt V-4, running four 7027A (6L6-type) power tubes on a silicon-rectified ~540V supply. Two channels each offer volume with Ultra Lo and Ultra Hi switches, feeding bass/treble controls and a selectable midrange. It is valued for a big, warm all-tube bass sound at a more manageable size than the SVT.

Years produced: 1971–1979
Made in: USA
Wattage: 100W
Channels: 2
Preamp tubes: 2× 12AX7, 1× 6K11, 1× 12DW7, 1× 12AU7
Power tubes: 4× 7027A

Tags: american, vintage, bass, high-wattage, 6l6, two-channel.

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.