D_Moorhead

Family - according to Tyne: Type A is similar to SE-1444, also with hard vacuum for amplification. Type B is a similar tube, but with a low vacuum for operation as a detector with 18-40 volts on the anode. Type C is similar to Type A, except that the grid is constructed of 22 turns of molybdenum wire with a pitch of 0.3 inch, instead of nickel - and for anode voltages of 80 - 500 volts. Type D is the unbased Electron Relay (ER) previously made by Moorhead. Type E is the British standard Type R, similar to Type A, but with spherical bulb and European standard four-pin base. Type F is similar to Type E, but with a low vacuum like the Type B. Type G is similar to Type C, but has a spherical bulb and an European standard four-pin base. It is the same as the British standard Type B tube.