What tubes does the Ampeg B-15NB Portaflex - Channel 2 use?

The Ampeg B-15NB Portaflex - Channel 2 uses 3× 6SL7 preamp tubes and 2× 6L6GC power tubes.

When was the Ampeg B-15NB Portaflex - Channel 2 produced?

The Ampeg B-15NB Portaflex - Channel 2 was produced 1962–1964.

Ampeg B-15NB Portaflex - Channel 2 preset

Verified · 89/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Ampeg B-12-NB and B-15-NB are Portaflex flip-top bass combos. Each channel has a 6SL7 with a passive bass/treble network and volume, and a 6SL7-GT paraphase inverter drives a cathode-biased pair of 6L6GCs from a silicon diode rectifier.

Years produced: 1962–1964
Made in: USA
Wattage: 25W
Channels: 2
Preamp tubes: 3× 6SL7
Power tubes: 2× 6L6GC

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

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.