The 42 is an audio output pentode, with a low output rating, but when used in push pull a pair could deliver 18.5 Watts in class AB2.

The construction of the electrodes is shown above. Note the control grid cooling fin sitting above the top mica.

See also 6F6 the octal version of this valve.

The balloon envelope is 53 mm in diameter and, excluding the UX6 base pins, is 118 mm tall.

 
Pin Connections

UX6	1	2	3	4	5	6
	h	a	g2	g1	k	h

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout
	6.3	0.7	250	250	-16.5	34	6.5	80k	2.5	3.2W

Thanks to Frank Philipse for supplying the above datasheet

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