The 12BH7 double triode is pin compatible with the ECC81,2,3 series from Mullard but has slightly different characteristics. Brimar do not give an intended use but the construction is compatible with audio through to low VHF use.

The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins the length is 57 mm.

 
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)	hct

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.6	250	-10.5	11.5	5500	3.1

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 04 June 2007