Dud 572Bs or others wanted.

[Kenneth G. Gordon]

I am conducting an experiment with a view to writing an 
article for Electric Radio magazine concerning reactivating 
"dead" power tubes which have thoriated-tungsten 
filaments.

What I am looking for are triodes (572B, 811, etc.), or 
others (813, etc.).

I don't want tubes that are completely burnt out. The 
filaments must light up, and there should be no shorts, i.e., 
grid to filament, or grid to plate.

I do not want "good" tubes.

I want tubes which in normal use, exhibit low or very low, 
way below normal, power output.

I will pay shipping to have the tubes sent to me, and will 
return any tubes the sender wants returned after I have 
finished with them.

However, if you want them back, let me know ahead of time 
since at least one of the methods I plan to test is rather 
extreme, and in at least 15% of the cases in which this is 
used, the filament will burn out, thus making the tube only 
good for display.

I will NOT replace any tube to which this happens, or which 
is damaged in shipping.

In many cases, the tubes I will work on will return to full 
output. For how long, I don't yet know.

For instance, one of my own Cetron 572Bs on which I 
recently operated rose from an output of 200 watts to an 
output of something over 650 watts, matching the output of 
one of the brand new 572Bs I am presently using in my SB-
200.

If this interests any of you, let me know what you think, off 
list.

Ken Gordon W7EKB

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