Best 6922 tubes for BAT VK300x ???

That estimation of price for a pair of CCa's would be correct. I've got six in my BAT VK-D5, and they were worth every penny. When a tube can affect the equivalent of a major equipment upgrade (vis-a-vis musicality): I'd have to say it's worth seeking out! Here's the vintage to look for: (CCahttp://cgi.ebay.com/CCa-Siemens-Halske-grey-plates-tubes-Match-Pair_W0QQitemZ260240926811QQihZ016QQcategoryZ64629QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) You can see the grey plate below the getter support in the pics. Some try to push later tubes off as the good ones, by not showing the correct angle on that plate. Here's a comparison that Aria posted on the 6DJ8 family, and it's variants: (http://ariaaudio.com/WV_Tubes.html)

BTW: Should you choose to go with tubes other than the CCa's, which were factory screened/selected for low noise already: Be certain that whatever you get is certified pre-amp grade. Any tube noise will be magnified exponentially if used in your BAT's front-end. I had an ARC SP-14 for a while and used a pair of Siemens E188CC's in the line section with excellent results.

It's all in what you want to wind up with, sonically speaking. Not knowing the end product you wish to accquire, some research is in order... try this spot for some insights... http://www.audioasylum.com/audio/faq/joes-tubes.html

That's where I began and the author is very close on many of his opinions of the different tubes... albeit, of those I've tried, that is.

AH- Something else I forgot to mention about the CCa's: They are a 10,000hr tube(as are the E188CC's), which makes them a bargain with regards to longevity and musicality. You'll note the writers that say the CCa is "too thin" never mention the vintage of the tubes tested. My guess is they were the later(inferior) tubes. There's a bit more support for the excellent Siemens E188CC on this site: (https://www.tubeworld.com/7308.htm) As well as more to read about the other members of the family.

Rodman99999, Great information. I can clearly see the grey on the CCa. Actually, the current price on that auction isn't too bad at this point. Germany ... is the item location. I had an individual here tell me that he heard no difference in the grey verses the shiney CCa's. Of coarse he has them for sale. I'd like to get a pair of these since your experience speaks for it's self. I appreciate the information ........