The 1S4 is a dry battery audio output valve.

The thin glass tube envelope is 17 mm in diameter, and excluding the base pins is 45 mm tall.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	f-	a	g1	g2	f-	a	f+

 
Absolute Maximum Operating Conditions

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	rl	Pout	D
	1.4	0.1	90	67.5	-7.0	7.4	1.4	0.1M	1.575	8,000	0.27W	12%

Thanks to Frank Philipse for supplying the above datasheet

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