The lifetime of a tube is determined by the lifetime of its cathode emission. And the life of the of a cathode is dependent on the cathode temperature, which means that it is dependent on filament or heater operating voltage.
Operate the heater/filament too hot, and the tube will give a shortened life. Operate it too cool and life may be shortened. This is especially true for thoriated filaments, which depend on replenishment of thorium by diffusion from within the filament wire.
For best, long lasting tube life it is recommended that you operate your tube within the tube manufactures specifications.
Operate the heater/filament too hot, and the tube will give a shortened life. Operate it too cool and life may be shortened. This is especially true for thoriated filaments, which depend on replenishment of thorium by diffusion from within the filament wire.
For best, long lasting tube life it is recommended that you operate your tube within the tube manufactures specifications.