The XFY10 is is a very small wire ended pentode and very probably was designed for hearing aid use. The 22.5 Volt anode specification fits with the small dry cells available.

The valve is the lowest power audio output valve we have seen at three mW. This power would be suitable for sensitive ear phone use only.

The thin glass tube envelope is oval in section 9 mm by 5 mm. The length excluding B5A wires is 38 mm.

 
Pin Connections

B5A	1	2	3	4	5
	a	g2	f+	g1	f-g3

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm	Pout
	1.4	0.025	22.5	22.5	-1.25	0.5	0.2	0.35	0.003

This exhibit was last updated on 02 August 2006