[Riggaberto]

I recently picked up a used Ray Samuels Raptor from head-fi, which I love. I was researching possible tubes to experiment with and I noticed that there is one called Raytheon 5687WA. I currently have some GE tubes in the amp and they're designated 5687WB. 
 
I'm new to tubes and wondering if someone could help explain the WA-WB difference or has any other advice. It doesn't appear to be the most common tube type but I've heard good thing about the Tungsols.
 
Cheers

 

[wuwhere]

I got this from Brent Jessee's audio tube site:
 
"The W is the military type code, A,B, and C are progressively later productions. These are nice military spec tubes. DO NOT confuse these with current production Russian or Chinese crap with the suffix WX, WB, or WC! These are not military tubes and are not NOS tubes at all!"

 

[Spareribs]

I wouldn't worry too much about the label codes generally but on the other hand, sometimes it's fun trivial info. If you are new to tubes, take it easy and enjoy the tubes you have now. Most tubes are actually pretty good. If you decide to venture into some more vintage tubes, have fun and enjoy. Lots of nice tubes out there but keep in mind that expensive tubes do not always mean they are better.