Ampeg b 15 serial

Originally designed by Jess Oliver, the main characteristic of the Portaflex is that the head of the amplifier is stored inside the cabinet and flips over when being used.

The Portaflex line has many different configurations. Ampeg manufactured the Portaflex SB model amplifier from This lightweight 67 pound cabinet incorporated the flip-top design of other larger Portaflex amplifiers of the time. Although the SB isn't as well known as the more powerful B, it is still highly sought after by musicians who use it mainly for studio recording. Tone Tips. Bass Bench. Joe Gore's Recording Guitarist. Vintage Vault. Esoterica Electrica.

Mod Garage. Bottom Feeder. PG Giveaways. Stay Connected. Enter email address Subscribe. Ampeg BN Portaflex. History and value of the Ampeg Portaflex. Can you tell me a little about my B and what it is worth today? Also, do you know of where I could get a replacement Lucite plate? Hull created an upright bass pickup by mounting a transducer on an extended peg that was inserted into the body of the bass.

Hull received a patent for his amplified peg Ampeg design in November and began manufacturing them in New Jersey with his new partner, Stanley Michael. Shortly thereafter, Hull and Michael went their separate ways and Hull moved Ampeg to Manhattan where he slowly began building amplifiers and developing the Ampeg name.

Ampeg was always trying to perfect the tone of their amplifiers and Oliver began experimenting with designs such as a double-baffle porting system and a closed-back reflex cabinet. Oliver also borrowed a design from an old sewing machine where the unit would flip out of the cabinet.

The first Portaflex amp was formally introduced in as the B Separate head and speaker cabinet systems, often referred to as piggybacks, became a solution in the early s, but it also negated the portability of the combo. The Portaflex addressed both of these issues, as the electronics were mounted on the top panel that could be flipped over.

Ampeg did utilize serial numbers when producing their amps, but these numbers can sometimes be inaccurate. The best way to date an Ampeg amp is based on its specific features and characteristics.

Identify physical characteristics of the amp that could determine its era. The first generation of Ampeg amps were small bass combo amps, usually brown or blue in color. Their grill cloths were often a circular shape. Blue checkered grill cloths were '60s designs. Functionally, the two features operate similarly, but you can always spot a BNB by the presence of an XLR speaker jack, blue-checkered vinyl, and a lack of an impedance switch on the back panel.

The BNC is most easily distinguished under the hood by its printed circuit board, double-baffled cabinet structure the last of its breed , and a reintroduced tube rectifier. Toward the end of , the BNB regained its rectifier tube and appropriate power transformer, and was re-dubbed the BNC.

Instead of reverting to the 5U4GB rectifier used in the primitive B, Oliver chose to use a 5AR4 tube rectifier that supplied less voltage drop or sag. The BNC also was one of the first if not the first Ampeg amp to use a printed circuit board, drastically optimizing production times. Similarly, Ampeg shifted the wiring behind its tone stack to a wired, plastic-coated, integrated circuit. This updated B still maintained its 25W power rating, yet the new model did drop voltage down.

The CTS speakers were far more rugged than the Jensens and also provided much sturdier bass response. As you can expect, these amps are extremely rare. Around this time, Ampeg also introduced the B N, a behemoth amplifier endorsed by artists like Roger Waters.

Showcasing an inch speaker, the B ran on entirely different circuitry. The power tubes were As, pumping out 50W of tube power. The preamp tubes also were different from the Bs contemporaries, employing two 6SL7s, coupled with a phase inverter. The earlier models used a solid-state rectifier, which offered bassists less voltage loss on bass notes, but later versions used a 5AR4 rectifier tube.

Since this change was so minor, Ampeg decided against changing the model name entirely. By mid, Ampeg decided to make the switch to a single-baffled porting structure and fixed-bias power tubes. The switch to fixed-bias tubes offered a lot of benefits for a bass amplifier.

For one, they have a firmer, cleaner sound, but diminished sustain and dynamic responsiveness. Fixed-bias tubes also require biasing when changing power tubes, and they also need to be checked from time to time to ensure that the amp is responding properly. Finally, cathode or self-biased amps are less efficient.