The SP13 screened amplifier pentode was introduced in 1934. This version has the Ct8 base and the similar SP13C has a B7 base. The use would have been for HF amplification in radio receivers. It is a non variable-mu valve and was displaced in favour of the variable μ pentode when TRF receivers gave way to mass produced superhet receivers.

The classic envelope is 40 mm in diameter, and excluding the Ct8 base pins, is 104 mm tall.

References: Datasheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type SP13 was first introduced^¶ in 1934.

 
Pin Connections

Ct8	1	2	3	4	5	6	7	8	tc
	m	h	h	k	g3	-	g2	a	g1

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	ra	gm
	13.0	0.2	200	100	-	3	1.3M	2.2

PDF scanned from an original document held by the museum