[Amps] SB221: Can you saftely mix and run an Eimac 3-500Z with and RF Par...

[Gudguyham at aol.com]

In a message dated 4/4/04 10:19:29 AM Eastern Daylight Time, jaking at es.co.nz 
writes:


> How much can you safely miss match tubes? Does this extend so far
> that one could run an different brand tube, Ie an RF parts 3-500ZG-RF or a
> Taylor 3-500ZG with and Eimac 3-500Z?
> 
> 

Hello Jeff, have a look at the tube, I will bet that the pin came unsoldered 
from heat and sparking occurred in between the tube pin and the outer pin.  
The sparking causes an insulation type deposit between the inner pin of the tube 
and the outer pin.  If you can generate enough heat to remove the outer pin, 
clean it up and the outer pin and re-silver solder the pin back on, the tube 
may still be good.  Take an ohmmeter on lowest scale and measure the filament 
resistance using the tips of the probe underneath the isolated base of the tube 
where the pin emerges from the glass.  Read the resistance of the filament, 
it should be about .6 ohms.  If it is, then measure the resistance using the 
pin.  If it is higher, that proves the connection of the tube pin to the outer 
pin is bad.  You may be able to save the tube if you can resolder the 
connection after you clean up the sparking deposits.  Good Luck and let us know.  As 
far as the mixing of tubes, Perhaps the 2 mismatched will work OK, maybe it 
won't.  Try it out and see what happens. That is the only real test.  I do not see 
any problems with testing them, the only thing that can happen is that less 
than optimum performance will be realized.  You may be surprised that it will 
work just fine!  73 Louie