The Pen44 is a beam tetrode audio output valve for single ended or push-pull applications. The valve specification allows for up to 18 Watts anode dissipation and suggests self bias operation rather than fixed bias.

The top view of the valve shows both the etched lettering and the top mica holding the electrodes firmly in the dome of the envelope.

Thanks to Leif Ekornrxd (LA9IM) for the pictures. Click here for Leif's site.

The classic envelope is 54 mm in diameter, and excluding the MO base pins is 100 mm tall.

 
Pin Connections

MO	1	2	3	4	5	6	7	8
	h	k	a	g2	g1	m	-	h

 
Absolute Maximum Operating Conditions

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm	rk	rl	Pout	D
	4.0	2.1	260	270	-11.1	70.0	12.0	10.6	135	3,000	8.0W	7%

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 21 February 2008 {find valves by name}