This is an original 845 of American manufacture. The label on the side is from the BBC valve section and so has some pedigree.

The anode is held by multiple rods welded onto a retaining collar that is clamped to the pinch support tube.

This audio power triode has an anode dissipation of 100 Watts and operates with 1250 Volts on the anode. The thoriated tungsten filament is powered at 10 Volts and 3.25 Amps.

This type of valve is still made in China and provides an excellent way to a single ended class A amplifier.

The wide glass tube envelope is 54mm in diameter, and excluding the special base pins, is 186 mm tall.

 
Pin Connections

	1	2	3	4
	g1	f	a	f

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	gm	μ
	10.0	3.25	1,250	-145	90	3.1	5.3

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 02 February 2008 {find valves by name}