This valve is probably a type AF3. The most prominent marking is the Bal716.

This German valve is marked with the makers name on one side and 'Wehrmacht' on the other. The C78 base was much more popular in continental Europe than in the UK. The Philips owned Mullard company made a range of Ct8 based valves in the 1930s.

See AF3 for details.

The classic metalised envelope is 37 mm in diameter and, excluding the CT8 base pins, is 100 mm tall.

 
Pin Connections

Ct8	1	2	3	4	5	6	7	8	tc
	m	h	h	k	g3	-	g2	a	g1

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	4.0	0.65	250	100	-3	8.0	2.6	10M	1.8

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 02 February 2008 {find valves by name}