The EL42 is an audio output pentode of an early all glass design. In single ended Class A an output of 2.5 Watts was to be expected. This was sufficient for most car radio receivers, but a pair in push-pull would generate a respectable 5.5 watts for larger receivers and audio equipment.

The envelope has made in Holland printed on it. The indentation at the junction of the foot and the envelope is characteristic of Philips production.

The EL42 took over from the EL2 and EL32 and was in turn replaced by the EL95.

The thin glass tube envelope is 21 mm in diameter, and excluding the B8A base pins is 53 mm tall.

References: Datasheet, ³⁰⁰² & ¹⁰⁴⁰. Type EL42 was first introduced^¶ in 1947.

 
Pin Connections

B8A	1	2	3	4	5	6	7	8
	h	a	ic	ic	g2	g1	k	h

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	rk	rl	Pout	D
	6.3	0.2	225	225	-10.0	26.0	4.1	90,000	3.2	360	9,000	2.5	10%

Thanks to Frank Philipse for supplying the above PDF datasheet

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