Best 6922 tubes for BAT VK300x ???

The "best" are the Siemens CCa's. Their E188CC/7308's are no slouches either. Of course- Telefunkens are way up there on the list also. We're talking transparency, extension(both directions), dynamics, liquidity, imaging and sound stage(ambience recovery) here though. Some people like a "warmer, sweeter" (microphonic) presentation, and consider that "better". If your tastes run that way- the Mullards, Brimars and other Brit tubes will please you more.

I should have mentioned: If you do consider the CCa- Make certain to buy NOS from the 60's, with the dull grey plate beneath the getter support. If it has a shiny plate, or date code plate inside, it's from the later production and will singe your ear hairs with it's stridency. Happy listening!

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.

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.

Not a problem Mr Z. When I got my last ones, four came from W. Germany and two from Argentina. They've functioned perfectly for me. The seller of the pair I showed you posted complete specs, and good pics which are confidence builders in my book(of course- I'm not the one buying them). Let us know your reactions to the differences they make. Happy listening!