The EL85 appears to be the little brother of the EL84 pentode. It is specified for single ended audio applications with a load resistance 9000 Ohms. This could be used in radio or television receivers.

The following is taken from a trade announcement in The Radio Constructor, March 1954. under the heading of - a versitile low current consumption miniature output pentode.

Mullard Ltd. announce the availability of the EL85 AF and RF Output Pentode. This is a noval-based (B9A) valve intended for AC mains operation. The heater rating is 6.3V, 0.2A, which is low in view of the maximum cathode current rating of 35mA. The EL85, which has an anode dissipation of 6 Watts, may be used as an AF output valve or as an RF amplifier up to 120 Mc/s (MHz). As a Class A audio amplifier it gives an output of 2.8 Watts when operated with an HT supply of 225 V and an anode current of 26 mA. As an RF amplifier, it will deliver 2 Watts at 100 Mc/s.

The EL85 should be of great use for equipments requiring moderate power out-put and where low LT drain is important. It is particularly suitable for mobile transmitters and receivers, where it may be used as a driver, modulator, or audio output valve.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 58 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type EL85 was first introduced^¶ in 1954.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	g1	g1	k	h	h	g3	a	g3	g2

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout	D
	6.3	0.2	225	225	-10.8	26	41	90k	3.2	2.8W	12%

Thanks to Frank Philipse for supplying the above PDF datasheet