Sensibly equivalent¶ to:
The HL13 was made by Mullard with two base cap options, Ct8 and B7. The Ct8 based version was called the HL13 and the B7 base option the HL13C. Although not in the literature Mullard also made a B5 based HL13. Mullard describe this valve as an indirectly heated medium impedance triode for use in DC/AC mains receivers.
Hivac also made an HL13 but only in B7 base and the characteristics differ slightly from the Mullard. The essential difference is that the Mullard version has a 13 Volt 200 mA heater, whereas the Hivac uses a 13 Volt 300 mA heater.
The use for the valve would have been as an RF amplifier in radio receivers.
The reverse of the glass is just the plain Mullard gold coloured zinc paint. The pins are plated a gold colour.
The classic envelope is 42 mm in diameter and, excluding the Ct8 base pins, is 103 mm tall.
References: Data-sheet & 1043. Type HL13C was first introduced in 1935.
Absolute Maximum Operating Conditions¶
Updated March 13, 2014. shape:classic construction:pinch type:triode age:1930.1940 base:ct8 heater:200ma pins:8 pin:1.m pin:2.- pin:3.- pin:4.h pin:5.h pin:6.k pin:7.a pin:tc.g1