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.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated December31, 2012. shape:classic construction:pinch type:pentode age:1930.1940 base:ct8 heater:200ma pins:8 pin:1.m pin:2.h pin:3.h pin:4.k pin:5.g3 pin:6.- pin:7.g2 pin:8.a pin:tc.g1