The Ampeg B-12N is a classic bass amplifier produced between 1961 through to 1964. It's circuitry was identical to that of the B-15N model, but it featured a 12" speaker.
The B-12N produces the same unmistakeable thick and gritty Ampeg sound. Its circuit design is identical to that of the B-15N (which featured a 15" speaker). The B-12N offered two cabinet options, namely the Jensen C12N and the JBL D-120F.
The B-12N is a two-channel amp with a volume control for each channel and a single set a shared Baxandall-type bass and treble tone controls. The circuit was relatively simple and included a 5U4G rectifier tube, a 6SL7 preamp tube for each channel, a 6SL7 phase inverter and a pair of cathode-biassed 6L6GC power tubes. Throught its production various modification have been made in the tube complements.
The amp is part of the Portaflex line of Ampeg amplifiers and as such, it features a removable tilt-back leg which allowed to be angled up around 30 degress. What's more the Portaflex line featured a Preamp Out jack which allowed another amplifier to be instered in a master-slave configuration.
The Gear Rack