Where to buy NOS 6L6 Tubes

Where is the best place to find 6L6 NOS RCA Black plate Output tubes for my Audio Research amp. I've heard that they are the best but I really don't know for sure. I'm using Svetlana 6L6 now and would like to upgrade.
check this Ebay auction, it is only three, but you get an idea.http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1210239683
I have three NOS 1614(6L6) and 2 used 1614(test like new) and 1 pair of NOS 6L6 tubes that I would like to sell. They are all metal tubes. Interested?
You could possibly also try 5881 Tungsols or KT-66's. Check with your dealer.
I have heard from quite a few people I trust that Kevin Deal is a great guy for expertise, quality of service and well tested NOS. I talked to him on the phone when I was searching for a new phono preamp. A real pro. Check out a great article/interview with him at www.soundstage.com and his website at www.upscaleaudio.com.