Sylvania 6sn7GT, 3-hole, bottom getter "bad boys" are a step up from the GTA chrome domes. I know people like to recommend Ken-rad dark glass but fail to mention non-microphonic ones are very hard to find. Early RCA 6sn7GT are quite nice too. Since Russia is in the news so much lately, how about the Melz 1578, black plates with round holes? Some say they are the best sounding 6sn7 ever made, certainly the best out of USSR. I like them.
