Siemens 6922. Besides my Siemens I have an Amperex 6922, GE Smokie ECC88, JAN Philips 6922, and Tesla 6922. My Siemens 6922 (possible CCa) wins hands down, no question. For gaming however I run my GE Smokie because it seems stupid running an $85 tube for gaming.
Here is a good deal on a RCA labeled gold pin Siemens 6922. You can find out who actually made it by the codes on the metal frame inside the tubes (RCA didn't produce tubes in Germany). For example I have an Amperex 6922 that is a labeled RCA and it was made in West Germany. It may not be as cool as it saying Siemens, but you can't beat that price or the quality of that type of year from Siemens. I did see
these also, which are Siemens labeled and the tests are very very good for $50, but you don't know which out of the 4 tubes you are getting. I would assume you can select which one when you buy since he has 3 left. I'd say that is also worth checking into, maybe even more than the RCA labeled one. There are a lot of good deals on Ebay and I have only purchased NOS tubes from Ebay with not a single problem. If the seller has good feedback on selling tubes and they list the equipment (or picture of tube during testing is even better, but cost more), you normally have nothing to worry about and the EBay 14 day return applies to them still.
$53.50 shipped if you do buy it now, but I bet he would take $40-$45.
http://www.ebay.com/itm/1969-Siemens-6922-6DJ8-Gold-Pins-Wide-Getter-Support-A49G-94-89-TV-7-/321639510654?pt=LH_DefaultDomain_0&hash=item4ae335727e
It's not perfect, but a perfectly balanced Siemens 6922 like the one I have runs between $85-$200 depending on the seller. However some days you may see one for $50 that is almost perfectly balanced, but it is very rare someone with the equipment and knowledge would price it that low as these tubes are very sought after.
Just for example here is a pair of Siemens 6922 labeled RCAs for $400:
http://www.ebay.com/itm/2-new-tubes-Siemens-RCA-6922-Gold-pins-factory-matched-NOS-NIB-Germany-1960s-/121373360670?pt=LH_DefaultDomain_0&hash=item1c426a821e