[Jeb Listens]

Hi all, 
 
Apologies if this has been asked before - I'm sure it has - but I just can't track down a post.
 
I'm just in the process of acquiring some NOS and used tubes for my new woo amp.  Some of the pictures of the tubes on eBay have marks on the tubes, on the glass, like brown or black "smoke" marks.  
 
If the listings are from reputable sellers and they say that the tubes have been tested and are OK is it anything to worry about?  and do you know why/what these marks are?
 
Thanks!
 
Jeb

 

[KG Jag]

Over the decades, I have seen all kinds of things with regard to tubes.  My EE dad, who changed many tubes from the 40's into the 60's, almost always used his tube tester.

 

[Jeb Listens]

Thanks KG - Is it possible to tell if something like this would affect the performance of the tube in any way if a seller says that it is NOS and fully tested?  
 
 

 

[GrindingThud]

That is the getter flash.... Silvery color is good, white powdery is bad. Almost all tubes have it and need it to stay working.
http://en.m.wikipedia.org/wiki/Getter

 

[KG Jag]

  Thanks KG - Is it possible to tell if something like this would affect the performance of the tube in any way if a seller says that it is NOS and fully tested?  
 
 

 
If it is true that the tube is fully and properly tested, it should be fine.  The remaining life of such a used tube is usually a crap shoot.

 

[Jeb Listens]

 
 
 
Quote:

   
If it is true that the tube is fully and properly tested, it should be fine.  The remaining life of such a used tube is usually a crap shoot.

 

That is the getter flash.... Silvery color is good, white powdery is bad. Almost all tubes have it and need it to stay working.
http://en.m.wikipedia.org/wiki/Getter

 
 
Cheers guys, much appreciated. 
 
Regards
 
Jeb. 

 

[billybob_jcv]

That is the getter flash.... Silvery color is good, white powdery is bad. Almost all tubes have it and need it to stay working.
http://en.m.wikipedia.org/wiki/Getter

Cool - I love learning something new!