has anyone else experience this.....

that's what I think as well, actually they blew out my preamp, repair guy said it blew a resistor, was pulling 6amps which it should not have.............

I agree with Al, that NOS should mean the tube has not been used in anyway whatsoever, however this is usually not true in so many cases.

Here are a couple of good articles by Brent Jessee about NOS tubes,

NOS Tubes: New Old Stock or Nasty Old Stuff?

A BRIEF NOTE ABOUT NEW OLD STOCK TUBES

Brent Jesse is a very reliable seller, but IMHO, some of the NOS tubes may possibly be slightly used, however do exceed rigorous testing for NOS. I have read many times that even a good slightly used old tube can still be much better than some of the new production junk. The problem lies with everyone acquiring old tubes calling them NOS regardless of the condition..

I used to questioned NOS tubes that did not come in original box, however found out that this means nothing. A poor used tube can easily be place in an original box. The box of a NOS tube may have deteriorated over years. Also, I have some very rare NOS Brimar black plate 12AT7's from 1955 that came in a bulk pack of 100, so no individual box, however, I do have the original bulk box.

Elizabeth also brings up a good point about tubes being relabeled, so it is important to know the physical characteristics of the internal structure for a particular tube.

It is always best to purchase from a reliable seller that offers a guarantee.

I normally get my tubes from andy of vintage tube, put had been calling around talking with some of the other pundits selling tubes and got burned so to speak...

TLS, thanks for the good articles, and the good points you provided in your post. As you and Bill_K indicated, the term NOS is unfortunately used too loosely too often. With the problem being further compounded by the existence of fakes, as Elizabeth pointed out.

As a potential purchaser, everything else being equal I would feel much more comfortable purchasing from a seller describing a tube as "used but tests as new" than from someone who simply describes it as NOS.

Also, I must say that personally I wouldn't want to be without a good tube tester (I have a vintage Hickok 800A), in part to minimize the possibility of component damage such as the OP has unfortunately experienced.

Best regards,
-- Al

Fake Mullards? What's next, fake Badboys? Fake Tung Sol Round Plates?