Ampeg B-15NF PortaFlex - Channel One preset

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

The B-15NF PortaFlex is a later-series flip-top bass combo with additional feature refinements over earlier NC and N models. Channel One retains the warm, punchy character of the classic PortaFlex circuit. The F suffix typically denotes a front-panel configuration update and driver stage modifications.

• Years produced: 1966–1970
• Made in: USA
• Wattage: 30W
• Channels: 2
• Preamp tubes: 3× 12AX7
• Power tubes: 2× 6L6

Known for: James Jamerson.

Tags: bass, american, vintage, low-wattage, clean, studio.

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.