The 6SN7GT is a glass tubular version of the 6SN7 double triode valve. Each half of the 6SN7 is electrically equal to the 6J5 triode.

The construction uses a glass pinch and two separate electrode structures are visible through the envelope, the cathodes are separate.

The 6SN7 was designed for audio applications and is still used for valve hi-fi.

The wide glass tube envelope is 27 mm in diameter and, excluding the IO base pins, is 64 mm tall.

References: Datasheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type 6SN7GT was first introduced^¶ in 1941.

 
Pin Connections

IO	1	2	3	4	5	6	7	8
	g1(2)	a(2)	k(2)	g1(1)	a(1)	k(1)	h	h

 
Absolute Maximum Operating Conditions^¶

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.8	250	-0	3	7.7k	1.6

Thanks to Frank Philipse for supplying the above PDF datasheet

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