Sensibly equivalent¶ to:
10LD3 141DDT 14L7 DH118 DH142
The UBC41 is an early all glass valve and less clear or free from imperfections than later valves. This is a double diode triode valve on a B8B base. Mullard describe the UBC41 as a high gain triode for use as an AF voltage amplifier, combined with twin diodes, for DC/AC mains operation.
The eight pins are equi-spaced around the pin circle and location into the valve holder is aided by the metal skirt. This valve is not special in its performance.
In general, TV sets using a series heater chain had to use 0.3 Amp 'P' series valves so that the total voltage of the heater chain (17 valves, say, plus tube) was less than around 170 V. This was to allow operation from 200/210 V mains after making an allowance for voltage drop in a series surge limiting resistor.
'U' series valves such as the UBC41 and UABC80 had 0.1 Amp series heaters and were intended for use in domestic radios (etc.) where only 4 or 5 valves are required so the heater voltage drop per valve can be greater.
The number of equivalents suggests that this was a standard type.
The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 55 mm tall.
References: Data-sheet & 1040. Type UBC41 was first introduced in 1949.
Absolute Maximum Operating Conditions¶
Updated March 12, 2013. shape:thin.glass.tube construction:all.glass type:double.diode.triode age:1940.1950 base:b8a heater:100ma pins:8 pin:1.h pin:2.a pin:3.g1 pin:4.s pin:5.a(d2) pin:6.a(d1) pin:7.k pin:8.h