While you are shopping for 6SN7's: Don't miss the Sylvania CHS, VT-231, bottom getter tube from the 40's. It's extension(without grain), transparency, liquid mid-range, slam and imaging are far better than anything manufactured today. They look like this: (http://cgi.ebay.com/Pair-Sylvania-Type-VT-231-6SN7GT-Driver-Tubes_W0QQitemZ150246460580QQihZ005QQcategoryZ73380QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) They are way less expensive than the best NOS 6SN7's(ie: TungSol round plate/bottom getter/6SN7GT or the Sylvania 6SN7W/tall bottle), but don't give up give up much to them. Just a few feet in the sound stage depth department, but back wall still goes way back in the right equipment. The Ken-Rad JAN CKR, VT-231 bottom getter is another excellent and inexpensive NOS tube that won't cost you a second mortgage. If you love your music: They are well worth seeking out. If you enjoy a more euphonic presentation: The RCA VT-231/JAN CRC, bottom getter is very nice tube. I agree that Upscale is an excellent place from which to purchase tubes(though he doesn't have the bottom getter Sylvanias right now). (http://www.upscaleaudio.com/view_category.asp?cat=93) Note that those recommendations only include one top gettered tube(the 6SN7W). The top gettered variants of the other tubes don't perform nearly as well.
