How do you test different tubes?


I hear people recommending different brand of tubes for amps, preamps, etc. My question is how are people doing this? Are there dealers who loan tubes like other gear? I would hate to have to purchase different sets of tubes, try them, find the one I like best, and then trying to sell the set I don't like.
bryans
I just spoke with Brent Jesse (audiotubes.com) regarding NOS 6SN7 tubes. He has an impressive supply of very high quality NOS tubes of all types. He allows you to buy, try, and return for upgrade or refund (-20% restocking fee). Although I didn't end up buying from him this time (I found what I wanted locally), I plan on doing so in the future.
I concur that there are legitimate vendors as named above along with the Tubedepot & Tubemonger that you can get quality new in box NOS tubes, and at reasonable prices which normally to my ears sound a lot better than the new production.
I use Hickock 752 and a TV7DU tube testers, but I just got a giant Sylvania tester that I have high hopes for. That's how I test different tubes.
NOS tubes are definitely available. Here on Audiogon I regularly see people selling off NOS tubes from their collections that they realize they will never use.

There are crooks out there so you have to be careful. It's best to have a tube tester if you are going to buy NOS or used tubes and buy from someone who will allow returns.

If you don't want the hassle of learning about tubes and tube testers, the tube sellers noted above can get you top quality tubes for a price.

IMO, NOS tubes can make a difference in the sound of your system that is worth the price.
Viridian: Please let us know how your "giant" Sylvania works out. I'm really curious to know how you came by it and at what cost!