Sensibly equivalent¶ to:
12BV7 12DQ7 7733
The 12BY7A is a 1950s video amplifier output valve designed for boosting wideband TV video signals to a sufficiently high level to be transmitted over a considerable length of cable without loss of quality.
This valve is labeled as being supplied by Tektronix and we can infer that the 12BY7A was selected for the stringent requirements of Y amplifier service in Tektronix oscilloscopes.
The heater is rated for 12.6 volt use and is centre tapped.
The detail in this picture reveals this to be a beam tetrode. Two wire grids, with copper supports, are visible. The bright surrounding structure is the beam forming plates. The dark boxes at the top and bottom are the two halves of the anode.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
References: Data-sheet, 1040 & Henning Hertz. Type 12BY7A was first introduced in 1955.
Absolute Maximum Operating Conditions¶
Updated January 27, 2013. shape:thin.glass.tube construction:all.glass type:beam.tetrode age:1950.1960 base:b9a heater:6.3v pins:9 pin:1.k pin:2.g1 pin:3.g3 pin:4.h pin:5.h pin:6.hct pin:7.a pin:8.g2 pin:9.g3