6922 Recommendation for my BAT VK-3iX Preamp

I run Siemens CCA grey plates in my BAT VK300x. SWEET !!! A NOS pair will set you back about $200.

I suggest Amperex US 7308 PQ White Label 60's, my reasoning is:
This is a quiet well balanced tube by design.
It presents hi's, mid's and lows evenly.(well balanced)
You can try them for a reasonable price.
You will hear your system through this tube.
By starting here you'll have a good idea where to go if it doesn't do it for you.
If you find you want more mid fullness you can go to Phillips Holland 7308 60's which is fuller in the mids etc.........
For more detail(less warmth also) Seimans CCA's etc...........

With the Siemens CCa's(pre 1969 ONLY- the later CCa was extremely strident), you will hear the music, not the system. Transparent, extended in both directions(without bloat of glare), liquid midrange, excellent imaging and soundstage. They were a tube specially built, tested and selected for silence and durability(10kHr) for the German Telephone service. Telefunken E188CC/7308 tubes are also very transparent(no added warmth or microphonic colorations). Of course- Some enjoy the "tubey", "warm", "sugary" colorations of British(Mullard, Brimar, etc.) tubes. The Amperex Company made some nice tubes that fill the middle ground. Be certain that whomever you purchase tubes from tests and certifies them as "low noise/preamp grade" tubes. I've got six CCa's in my BAT VK-D5, but- everyone must satisfy their own tastes. Happy listening!