I recently got some vintage military era 12Au7 and 12ax7 tubes tested!

And almost all of them were good!

These tubes I got from a merchant who sells at the local artist market.  I immediately noticed 

he had some real vintage brands and this struck my attention.  This is just a sample of what he and another merchant had. The brands included RCA, Phillips, Sylvania, GE, etc.  Some of the boxes were labeled CBS etc.  I have some of the boxes still.  Unfortunately, they were using them in large quantities to make art.  Some of the art was organite based sculptures, but I didn't think this use of the tubes helped them much.  They are way more valuable towards hi-fi audio and almost priceless. I was pretty bummed to hear that, but fortunately I salvaged all these and a couple more!  I tried a few and they sounded better than anything I had ever put into my tube amp's preamp before.  The best sounding one that I found was an RCA blackplate with the rough looking carbon black plates (look up on Tube King's page on ebay).  This one sounded extremely powerful and crystal clear on my clear channel on my Fender Hot Rod Deluxe.  I even found a popular Westinghouse vintage tube in there as well and some Phillips AU7s that matched each other.   I am putting some of these tubes up for sale soon.  The 12 AU7s were almost as loud as some 12 AX7's,  so they worked well in the Preamp section and were way easier to distort at lower volumes.  I may use a couple of these to build DIY preamps if they don't sell!