[Test-Equipment] 811A Tube Check & 1kw Amp

[Dale H. Cook]

At 02:59 PM 5/26/2004, Roger Agnew wrote:

>I'm wanting to check some 811A tubes in my Hickok 800A tube checker and 
>the 811A or 572B is not listed in the manual or on the "wheel" chart. Can 
>this tube be checked

Probably not. Most tube testers are designed for receiving tubes with their 
fairly conservative filament currents. The 811 needs 6.3 volts at 4 
amperes, and the filament transformers in most tube testers cannot provide 
enough current to raise its cathode to operating temperature.

The normal method of testing RF power tubes is in-circuit. An alternative 
would be a vacuum tube bridge, which uses external power supplies. A bridge 
would probably set you back $1,000.00 or more, if you could find one, plus 
the cost of the power supplies, generator and detector.

Dale H. Cook, Chief Engineer, WWWR Roanoke VA, WCQV Moneta VA, WKBA WZZI 
Vinton VA, WKPA WLNI WZZU Lynchburg VA, WMNA/WMNA-FM Gretna VA
http://members.cox.net/dalehcook/starcity.shtml