[Amps] tubes

[c s]

       I want to believe that in the "earlier" times , there were not 
too many mfrs.!! of any one type of tube. Insofar as the 572B was 
concerned, the earliest I can remember was the Taylor company. !!   I 
know that today, there is a company . (china)  from which I refuse to 
buy "any" tubes .!!! I know that "from past experience" these tubes are 
useless, above 28.00 mc W at ithout special ckts , and experience. !!!
       Just my thoughts!!!!!!!
       can any one tell me different ??
        would love to know !!!!!
        carl / kz5ca