12BY7A 12BV7 PENTODE

NOS RCA

RCA pentode vacuum tube amplifier using the Noval socket configuration.

The 12BV7, 12BY7, 12BY7A, and equivalents were a class of medium-low gain, pentode vacuum tube amplifiers using the Noval socket configuration. Although originally marketed as pentode tubes for use in early television receivers, they found additional uses in audio equipment. The 12BY7A was introduced in 1955 as a demodulated video signal amplifier for television receivers. Its design specifications called for linear gain along a wide bandwidth (approximately 4 MHz) with low transconductance (13 Millimhos (Millisiemens)) and high sensitivity. This combination of sensitivity, bandwidth and price lead to its popularity in audio amplification equipment. As used in Harman Kardon Citation II as preamplifiers.