[Boatanchors] TUBE TEST

[Magoo]

I just did some tests on a bunch 14) of NOS Russian 6550 tubes looking for a 
pair for my modded Ranger.  On my Hickok 605, every tube showed very good, 
in most cases exceeding the basic minimum for that tube.  HOWEVER, every 
tube tested did the same thing: the reading reached a peak and then began to 
slide back down, often below acceptable minimum.  Bad sign...I used to see 
6146 tubes and similar from FM radios with the same characteristic and 
consequent low power output.

Has anyone else had this same issue?  I know the tubes are brand new and 
about 10+ years old.  Is this a characteristic of the older Russian tubes on 
the whole?  How about the new tubes?  I'd hate to order a new pair today and 
find they do the same thing!

Bill, VE3NH