If you are having a problem you think may be tube related, its easy enough to check by listening and selectively replacing tubes, or if they are all old, just doing a complete re-tube of the amplifier and a bias set if necessary. 

I carry JJ tubes because they sound great in every application, are a very robust and high output tube even compared to vintage tubes, and I don’t have to worry about them coming back to me in a week because they died or got noisy.  

“Winged C”  Svetlana factory tubes such as SED, etc, are a good choice to in some applications.  NOTE:  Look for that “Winged C” logo if you want real Svetlana factory tubes.  The trade name “Svetlana” was purchased by New Sensor and tubes branded “Svetlana” are NOT made in the Svetlana factory!  (Confusing huh?).  They are about twice the cost of JJs but some folks swear by their EL34s. 

I can get just about any other current production tube you want on request, get them fast, and beat the local prices. 

I don’t deal in NOS tubes, at least not the expensive ones.  The good ones are getting more scarce by the day, and if you get addicted to them, you will be forced to quit cold turkey in the not so distant future.  You’ll also pay exorbitant prices for them.  If you buy them, be VERY careful that you trust the source.  There are a lot of dealers out there selling tubes as NOS (which stands for “New Old Stock”, meaning a tube that is old but has never been used) but they are in fact just “O”; i.e. old.  An RCA black plate 6L6 is a great tube NOS; its not so great used up and almost dead.  Same with a Mullard 12AX7, etc.  If you find a brand of NOS tube that you just love, keep a set for recording and use something else for gigging.