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Re: Max anode voltage?

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Original poster: David Speck <Dave@xxxxxxxxxxxxxxxx>


If tubes are anything like light bulbs, you may take a significant hit on filament longevity by running them at 10% overvoltage. I read somewhere that the life of an incandescent lamp varies as the inverse cube of the current, so that works out to about 75% of the rated lifetime.


With 10% more filament voltage you can probably double the saturation

I think that the effect of overvoltage on life is even greater than you state - there's information on it in my RCA Transmitting Tube handbook but it isn't handy right now. Depends on the filament (pure tungsten, thoriated tungsten, oxide-coated, etc.). On the other hand, life is probably not much of a consideration in TC work and some overvoltage is undoubtedly permissible.