>
>> > I don't believe its an issue of filamant "failure" or tube returns
>> > but one of reduced emission life. The addition of a simple rheostat
>> > to the power tube's filament circuit makes good engineering and
>> > economic sense.
>> >
>> > -Paul, W9AC
>>
>> Amen, Paul.
>> We are prolonging emisson here. An added bonus of a resistor/rheostat
>> in the primary of the filament transformer is a bit of inrush
>> protection that is there all the time.
>
>Put all those tubes laying around that are perfectly good except for
>low emission in one pile.
>
gold-sputtering reduces emission.
>Put all the tubes with internal defects like broken welds, leaking
>seals, open filaments, grids touching cathodes, and on and on in
>another.
>
>Now use common sense.
>
>Factually, emission life is an issue when the tube is operated at
>25% of its capability in uninterrupted commercial service. In
>amateur applications, its mostly something for people to talk about.
>
>
When is Mr. Rauch going to tell us why the 8877 needs no VHF suppressor.
Why did Henry Radio, Dentron and Alpha use a VHF suppressor in their 8877
amplifiers. ?
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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