Tried the RCA 6k6gt and have given up on them for now. None of the combos I tried were good enough to make me want to keep them in there. Put in these tubes:
These are a dead ringer for the GEC vt60. It took me a while to find a good input tube but it sure paid off when I did. The BL63 with these 807 have a deep, rich sound in my system. It also looks like super serious hifi. We all know how important that is!