The Pen26 is an audio output pentode. The first production was in 1934 with a revised form with 3.0 Watt output introduced in 1935.

The Pen26 was essentially an improved functional replacement for the Pen20, suitable for either AC or DC heater operation and therefore intended for universal AC/DC sets. Note the 200 mA heater rating. It seems to have been based on the same Philips European prototype as the Triotron Type P2060 and the Tungsram Types PP24 and PP24s, all of which have identical ratings.

An interesting feature of these ratings is the unusually low, for an output pentode, screen grid voltage rating (100V). This suggests that it was intended to be capable of useful power output when operating from 110V mains supplies. It is also interesting that unlike, for example, Tungsram, Mullard never marketed a version of this valve fitted with a B7 base cap. The Pen26 seems to have a distinctly European rather than British flavour and was perhaps used only in imported Philips sets.

The anode load impedance should be 3,000 Ohms.

The classic envelope is 43 mm in diameter and, excluding the Ct8 base pins, is 116 mm tall.

 
Pin Connections

Ct8	1	2	3	4	5	6	7	8	tc
	-	h	h	k	-	-	g2	a	g1

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm	Pout	D
	24.0	0.2	200	100	-19.0	40	5.0	3.1	3.0W	10%

This exhibit was last updated on 02 December 2007