The 12SG7 is a 12.6 Volt version of the 6SG7 pentode. The pins are compatible and the ratings are the same.

The 12SG7 is a variable μ design with a medium gain. It was obsolete by the early 1960s.

The thin metal tube envelope is 25 mm diameter, and excluding the IO base pins, is 50 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8
	m	h	k	g1	k	g2	h	a

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	ra	gm
	12.6	0.15	250	150	-2.5	9.2	1M	4

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}