Ampeg B-15NF Portaflex

The Ampeg B-15NF Portaflex is one of the most iconic and influential bass amplifiers in music history, renowned for its innovative design, warm tube tone, and enduring legacy in studio and live settings.

History of the Ampeg B-15NF Portaflex

• Introduction (1960): The Ampeg B-15 was introduced in 1960 as the first model in the Portaflex series, designed by Jess Oliver. Its name derived from its 'portable reflex baffle system,' which included the revolutionary 'flip-top' design. This allowed the amp head to invert and store inside the cabinet for easy transportation while protecting its delicate tubes. The B-15 quickly became the standard for bass amplification, offering a warm, full-bodied sound ideal for recording and live performance.
• Evolution to the B-15NF (1965): In 1965, Ampeg released the B-15NF ('New Fliptop'), an updated version of the original model. It featured a fixed-bias power amp, replacing the earlier cathode-bias design, which increased output power from 25 watts to 30 watts. The B-15NF also introduced a single-baffle cabinet design with a CTS speaker, enhancing its tonal clarity and projection. These updates solidified its reputation as a go-to bass amp for professional musicians.
• Tonal Characteristics: The B-15NF is celebrated for its warm, punchy tone with rich harmonic content, thanks to its Baxandall EQ circuit and tube-driven preamp (6SL7 tubes). It excels at producing fat low-end frequencies while maintaining articulate mids and smooth highs, making it ideal for bassists seeking a classic vintage sound.
• Legacy: The B-15NF became synonymous with studio bass tones during the 1960s and beyond, earning its status as 'the most-recorded bass amplifier in history.' Its portability and reliability made it a favorite among session players and touring musicians alike. Even decades later, modern reissues like the Heritage B-15 have kept its legacy alive.

Popular Settings

• Classic Bass Tone:
  • Volume: Set to around 5-6 for clean tones.
  • Treble: Adjust to 5 for balanced highs.
  • Bass: Set to 6-7 for a warm low-end emphasis.
  • Ideal for Motown or soul-inspired playing styles.
• Pushed Overdrive:
  • Volume: Increase to 7-8 for natural tube saturation.
  • Treble: Set to 4-5 to avoid harshness.
  • Bass: Keep at 6 for depth without overwhelming clarity.
  • Perfect for blues or rock bass lines.
• Modern Clean Tone:
  • Volume: Keep at 4-5 for pristine cleans.
  • Treble: Boost slightly to 6-7 for added brightness.
  • Bass: Dial back to 5 for a tighter low-end response.
  • Suitable for jazz or funk styles.
• Dynamic Playability:
  • The amp responds well to adjustments on the instrument's volume knob; rolling back can yield cleaner tones while pushing forward brings out natural tube compression.

Notable Players

The Ampeg B-15NF has been used by some of the most legendary bassists in music history:

• James Jamerson (Motown): His iconic grooves on countless Motown hits were recorded using a B-15.
• Donald 'Duck' Dunn (Stax Records): Known for his work with Booker T. & the MG's and Otis Redding.
• Chuck Rainey (Session Legend): Played on numerous recordings across genres using the B-15's warm tone.
• Bob Babbitt (Motown): Another key figure in defining the sound of Motown bass lines.

In later decades, players like Darryl Jones (Rolling Stones), Justin Meldal-Johnsen (Beck/NIN), and Owen Biddle (The Roots) have continued to champion its timeless sound.

Summary

The Ampeg B-15NF Portaflex remains an enduring symbol of bass amplification excellence, celebrated for its innovative design and unparalleled tonal quality. Its influence continues to resonate in studios and on stages worldwide.