What tubes does the Ampeg V-4B (1971) - Channel One use?

The Ampeg V-4B (1971) - Channel One uses 4× 12AX7 preamp tubes and 4× 6L6 power tubes.

When was the Ampeg V-4B (1971) - Channel One produced?

The Ampeg V-4B (1971) - Channel One was produced 1971–1979.

Ampeg V-4B (1971) - Channel One preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The original 1971 V-4B is a dedicated 100-watt all-tube bass head sharing its chassis with the V-4 guitar amp but voiced specifically for bass. Channel One delivers warm, authoritative low-end through four 6L6 output tubes. The V-4B became a popular gigging alternative to the heavier SVT, offering a more manageable form factor without sacrificing tube tone.

Years produced: 1971–1979
Made in: USA
Wattage: 100W
Channels: 2
Preamp tubes: 4× 12AX7
Power tubes: 4× 6L6

Tags: bass, american, vintage, mid-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.