Disappointing short life of NOS preamp tube

facten-

I've never  cared/paid attention to tube hours, but the amp /tubes have served me well.

Over the 6 year period there have been random marathon weekends of near 24 hour service, after work, almost daily 2  hour dinner sessions, random times the amp has been accidentally left on weekends(not recommended, of course) and BLAST your ears sessions with friends. 

Whatever it equates to, I consider the tube serving  it's purpose. I have a daily driver 67 Mac tuner  with a couple of original tubes. 

USA NOS tubes for the most part are indestructible, but not 100% like anything manmade.

good old stock 12au7’s are still plentiful and pretty inexpensive, your complaint falls on deaf ears with me... and if you only got 7 years out of your pair, you must be abusing your gear

he he he

As George Harrison said, All Things Must Pass.

I guess you should be glad it was just a tube and not you.

tablejockey - I may be wrong but my impression has been that preamp tubes are rated at 5-10,000 hours. Given your described usage you may have reached that over the 6-7 years

It sounds like around 5,000 hours.
 

I have heard NOS have long lives… but as a kid also remember taking tubes down to the tube tester at The local drug store. I suspect some over romanticizing. And of course “average life” has a bell curve distribution.