The EF85 is described as a VHF varible-mu pentode. Clearly this places the valve in a superhet context with AGC applied to the RF and IF sections. It was a television valve and the EF183, released in the 1960s, overtook its performance.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 60 mm tall.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	100	-2.0	10.0	2.5	0.5M	6.0

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 11 July 2007 {find valves by name}