Tube Test Results

Tubes begin dying on day #1 of use. After 1000 hrs., it`s conceivable it`s outputting 1/2 of rated pwr.

Yeah, your assumptions are more or less correct. Aside from identifying shorts, each tube tester has its own standards for what is passable and excellent.

Tubes do burn out in varying degrees depending on the tube type and how it's being utilized. I have a DAC that uses two 6922s and I'd leave that DAC on 24/7 for three or four years with very little noticeable degredation of the tubes.

My preamp goes through 6SN7s much quicker. It may have to do with the ones I use all being WWII era tubes or maybe it could just be the way they're being employed in the design of the preamp. But it gets expensive.

Power tubes can be even more costly.

Depends totally on the particular tube type and the component in which it's used. I have some Telefunken 12AX7s that have been in regular use in my phonostage for over 10 years, and they were used tubes in the first place. Mullard EL-34s also seem to last virtually forever. Some components stress their tubes more than others. As far as the tester is concerned, the good and excellent ratings are too often arbitrary, depending on how the user interprets the meter and how the meter is marked (my own tester has no position higher than "good" ). You're better off paying higher tube prices to a trusted/respected tube seller. I've been lucky in buying tubes, and I've been unlucky. I wish you luck. Dave

You're better off paying higher tube prices to a trusted/respected tube seller...
Dopogue  (Threads | Answers)

There simply is no better advice for a tube buyer.