The 12AX7 is a high impedance amplifier triode and equivalent to the Mullard ECC83 where full details can be found. Colomor imported and distributed foreign valves.

The thin glass tube envelope is 21 mm in diameter and the average diameter for B9A valves is 20 mm. Length excluding pins is 48 mm.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(2)	g(2)	k(2)	h	h	a(1)	g(1)	k(1)	hct

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.3	250	-2	1.2	62.5K	1.6

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 08 June 2007 {find valves by name}