The B309 is an RF double triode and a special quality version was also made. (QA2406).

The valve is equivalent to the Mullard ECC81.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 49 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(2)	g1(2)	k(2)	h	h	a(1)	g1(1)	k(1)	h(tap)

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.3	250	-2.0	10.0	10000	5.5

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 05 July 2007 {find valves by name}