[AMRadio] Screen Modulated 813


D. Chester k4kyv at charter.net
Tue Dec 12 13:10:49 EST 2006



> david knepper wrote:
>> If you have one tube like aan 833A running slightly cherry and the other 
>> is not showing any color, then, the latter is a weak tube.  The former 
>> has low emission, in other words.
>>
>
> Not all 833's are created equal.
> Your statement is not necessarily true.

Depends on the plate current.  It should be close to the same for each tube, 
with identical grid bias and/or grid drive conditions.  If the tubes are way 
off balance, chances are the low-reading tube is weak, or the high-reading 
tube is gassy.

It's best to have a separate plate meter for each tube, so you can always be 
aware of tube balance.

Don k4kyv 




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