The 12BY7A is a 1960s 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.

The heater is rated for 12.6 volt use and is centre tapped.

Henning Hertz comments that the 12BY7A was widely ised by radio amateurs in the 1960's and 1970's as a driver stage for a pair of 6146B tetrodes in the PA (final stage) of HF transmitters up to 30 MHz.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 54 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	k	g1	g3	h	h	hct	a	g2	g3

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.6	250	150	-68	25	6	110k	12

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 26 March 2008 {find valves by name}