>the filiament voltage ........ for the 4-250A tubes can you go over a
>bit, say to 6 volts?
The emissive life of a thoriated tungsten cathode/filament varies as
[e1/e2]^23.4. Or, in other words, each 3% increase in fil. V over what
is needed to produce normal emission, reduces emissive life by half. A
healthy 4-250A produces normal emission at c. 4.8V. If the filament is
operated at 6.0V, life will be reduced to [4.8/6.0]=0.8^23.4=0.0054, or
0.54% of the normal emissive life. (''Care and Feeding of Power Grid
Tubes'', Eimac Co.)
>will this adversly affect the tube what i really need to know will it
>kill it right away.
No. The tube should last c. 80-hours instead of the normal 15k-hours.
>What is the max filiament voltage any of you have put on this tube and
>made it last and preform to your satisfaction?
>thanks for any help you can give
>Chris NI4L
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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