RCAs were 1950s, iirc mid 50s, telefunkens were 1960s, matushitas were mid 60s as well, rest were made within the last 10 years so basically current production. The RCA blackplates were just head and shoulders better than anything else, including the telefunkens everyone raves about. We also tested 1960s mullards, they were horrible, muddy and dark. Bryce Youngman is the man for vintage tubes on bartertown, greengirl613 on ebay has great tubes too, well matched and she stands by what she sells. For new production tubes, I'd go with Jim McShane. For new production tubes, I also wouldn't bother with anything but the sovtek 12ax7lps, they bested the new issue mullards and genalex gold lion 12ax7s and for $12 or so each, are a bargain.