• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

WE 300B tubes.

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Hello everybody.
I need to know how to tell if a tube has been used or not, and your help is welcome..as usual !
A guy I know has six NOS Western Electric 300B for sale.
They are the ones with the yellow letters, and the number 152 in five of them, the other with the number 126. I understand this is a code for the year they were built..right?
The boxes (blue with a white section) are in a so-so condition. There is a code on the box: 10-51 or 5-51 or 4-51, which I was told mean the month and year of manufacture...(???)
He is asking $ 450 each, but maybe he will reduce the price if I buy the six tubes. I may consider buying two tubes and sell the other four.
They are supossed to be NOS, but I have no way to know if they are new.
Looking at 300B pictures at some web sites, it seems to me that the internal metal parts (the almost flat, big ones) look like plain gray metal, but my friend´s tubes look like metal but with (apparently) some light dark coating (it is not easy for me to explain this). How can you tell if used or new ??
Thanks for your help
Best regards.
Jose Bulnes
I can't count the number of times I've seen or heard someone say that they tested a tube and determined that it was 'new'. They are either misguided, or lying. There is no way to determine whether a tube has been used. The best you can do is test it and see if it has some life left in it, which is not at all the same thing as saying it's new.
The 'N' in NOS is often meaningless. The only thing you can count on is the 'O'.
I believe the 300's are being made again. Check around for pricing on current tubes before buying old ones.

Plug the tubes to an existing 300b amp...

There's no way 2 know if a tube was used or not. By the way, He's selling it to you on a good price. Good or bad, tubes tester is the only instrument you can use to check the 300b. Original or NOS 300b tubes are becoming rare like the Western Electric 300b. And they are sought for their sonic signature and longlife reliability.

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