The X429 is an early version of the 4X500A tetrode made by EIMAC. The anode material is very thin unlike the 4X500A that is thick and rugged. X number issued 12-45 and was a varient of the X421. Speculation is that this may be the first use of the folded ribbon cooling construction.

Length = 4.50" Diameter = 2.37"
Max voltage =
Max current =
Fil voltage = 5
Fil current = 12.6 amps         GOTO INDEX