I recently did some rolling with an Audiophile buddy with 6922's in our ARC-LS2B's. These amps are hybrid designs and use only a single 6922 tube so YMMV. In fact I believe observations regarding specific tube types would vary widely depending on what hardware you are putting the tubes in, so take all advice with a bag of salt. The LS2B's are definitely sensitive to tube choice. We rolled Tele CCa, Siemens CCa (Rohre) and Mullard E88CC's. Both of us liked the Siemens the best for the detail and focus it seemed to bring mostly in the mids and upper register. Of the three the Mullard was the warmest sounding, but at the expense of focus, and didn't seem to have as much dynamics in the mids and upper ranges. Since then my friend has been using a recommendation of Kevin Deal: the Rocket 6H30 and seems to like it VERY much. I understand it is not compatible with all hardware that uses a 6922, but cannot expand on that as I don't know the specifics. You may want to check those out too as they'd save you some $ at around $25-30 each. I have not heard it myself, but do respect my friends opinion.
Mdomnick and Dudeaudio: I need an education here regarding Amperex (you both mention using their tubes). I was under the impression that Amperex as a company did not actually manufacture tubes, but instead sourced them from various manufactures. Of course other companies do this as well but I was under the impression that Amperex exclusively sourced it's tubes and actually never owned or managed manufacturing facilities of their own. Is this true, or have I been mislead in this information? I have some wonderful Amperex 12ax7's that were actually manufactured by Tungsram in Hungary....just wonderful tubes for my application.
Good luck with your quest Jitmingl!