The 12AU7-A is a miniature medium mu twin triode intended for service in
radio and television receivers or in audio amplifiers. The tube is suitable for
use_ in a variety of stages, such as general-purpose amplifier, phase inverter,
oscillator, or multivibrator.
The electrical characteristics of the 12AU7-A and 12AU7 are essentially
equivalent. As compared to the 12AU7, the 12AU7-A exhibits a lower micro-
phonic output.
Except for heater ratings, the 7AU7 is identical to the 12AU7-A. In addition,
the 7AU7 incorporates a controlled heater warm-up characteristic and is
specially suited for use in television receivers that employ 600-milliampere,
series-connected heaters.