The Ampeg B-15N Portaflex of the 1960s, the "multi-instrument" successor to the B-12 amplifier, is considered the most recorded bass amplifier in history -- and with good reason. This all-tube "fliptop" bass combo amp pairs a 25-watt top with simple volume and tone controls to a double baffle 1x15 cabinet which contributes significantly to the deep, classic tone that the B-15N can get you in a heartbeat. The top tier of bass players quickly adopted the B-15, including James Jamerson, John Paul Jones and Bill Wyman, and these amps remain studio staples even today. When it comes time to move the B-15N, the top can be flipped and secured inside the cabinet for transport, giving you the portability of combo amps and the stability and flexibility of piggyback stacks. The B-15N evolved fairly constantly through its production, with the 1970s seeing the dawn of a 4-input model with a more extensive EQ similar to the one found on an SVT or V4. The '70s models can still be had for quite the bargain and, in the right hands, can sound every bit as good and creamy as the originals from the 1960s.