The EL38 was designed as a television line output valve. In the early days of CRT based television the tubes could have been either electrostatic or magnetic deflection. The EHT supplies were probably derived from special mains transformers and ran at about 10 - 14 kV. Thus the line output valve was not as heavily stressed as later types had to be.

The EL38, designed in the late 1940s, was able withstand a positive anode surge of 8,000 Volts and in addition to the 25 Watt anode dissipation the screen grid was wound to withstand a dissipation of 8 Watts. The cathode is oval, and the ceramic insulators are clearly visible.

The classic envelope is 42 mm in diameter and, excluding the IO base pins, is 119 mm tall. This is slightly different to the Mullard version.

References: Datasheet & ¹⁰⁴⁰. Type EL38 was first introduced^¶ in 1946.

 
Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	g3	h	-	g2	g1	-	h	k	a

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	mAa	mAs	Pdiss
	6.3	1.4	300	250	64	18	25W

Thanks to Frank Philipse for supplying the above PDF datasheet

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