The E83F Mullard pentode is a special quality version of the EF83.

The valve was designed for class A audio amplification in telephone equipment where long life was very important. The audio output was 0.87 Watts and the maximum anode dissipation was 2.1 W.

The thin glass tube envelope is 19 mm in diameter and, excluding the B9A base pins, is 57 mm tall.

Reference: Datasheet & Philips Pocketbook for Hams 1962. Type E83F was first introduced^¶ in 1958.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	mAa	mAs	ra	gm
	6.3	0.3	210	120	10	2.1	0.5M	9.0

Thanks to Frank Philipse for supplying the above PDF datasheet