What tubes does the Ampeg B50 - Main use?

The Ampeg B50 - Main uses 3× 12AX7 preamp tubes and 4× 6L6 power tubes.

When was the Ampeg B50 - Main produced?

The Ampeg B50 - Main was produced 1965–1969.

Ampeg B50 - Main preset

Close · 72/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The B50 is a mid-power Ampeg bass amplifier delivering 50 watts from four 6L6 output tubes. The Main channel delivers clean, reliable bass amplification with more headroom than the PortaFlex combo series. A practical step up from the 30-watt PortaFlex models for larger venues.

Years produced: 1965–1969
Made in: USA
Wattage: 50W
Channels: 2
Preamp tubes: 3× 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.