The EBF80 is a variable μ amplifier pentode and a pair of signal diodes in the one envelope. Probably this was designed, as was the later EBF89, as final IF amplifier and AM detector. The other diode would provide AGC rectification.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 58 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	g2	g1	k,s	h	h	a	a(d1)	a(d2)	g3

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	85	-2	5.0	1.75	1.4M	2.2

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 10 June 2007 {find valves by name}