Original poster: David Speck <Dave@xxxxxxxxxxxxxxxx> Robert,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.
Dave
With 10% more filament voltage you can probably double the saturation current.