The only way to know for sure is to..........

Tubes Asylum

Questions about tubes and gear that glows. FAQ

In Reply to: Re: Ok why should you leave the CDP on? posted by feet's too big on February 16, 2003 at 05:44:04:

test your tubes after a bit and see. I've read that the magical number for audio applicaltions is 85% and we know that many tube manufacturers used the 65% or 60% cutoff as their throw-away point, so you don't have much room regardless.
One would be surprised by how some gear bangs on a tube, cold starts notwithstanding. I recently replaced some Munich made Siemens 6DJ8s that came with my new SF Phono1 SE stage and prior to me installing the unit for the first time 20 months ago, I tested all four and rematched them up. All four tubes were over 100% on my Triplett 3423 testor.
When I yanked them out two weeks ago, after on/off moderate use, two were down to 70% and the other two were at like 75%, so they got banged a bit. I was surprised because I don't listen to records everyday, although sometimes I would keep the SF powered up for a couple of weeks at a stretch.
My Blue Circle Galatea 3.1 preamp, on the other hand, uses the same tube family and the front gain stage socket really creams a tube. The buffer less so. If I leave my preamp on for 24/7, which I've done a lot over the three years, I'll get 6-8 months out of a tube and this blows. However, at least I can measure the decrease and judge accordingly. I'm now turning if off when use isn't anticipated.
One really needs to know how their piece of gear treats a tube and most manufacturers will just spout the party line--like the 7308 being a 10,000 hour tube, so don't worry about it.
Take care, Chris

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Follow Ups Full Thread

Topic - E288CC life - Christophe 15:57:01 02/15/03 (9)

Tube life in your Ah! Tjoeb, and standby - Kevin Deal 10:03:59 02/16/03 (0)

Re: E288CC life - Christophe 09:00:36 02/16/03 (0)

Re: E288CC life - Carlos 17:43:54 02/15/03 (0)

Re: E288CC life - feet's too big 16:14:43 02/15/03 (5)

Ok why should you leave the CDP on? - airtime 16:38:28 02/15/03 (4)

Re: Ok why should you leave the CDP on? - feet's too big 05:44:04 02/16/03 (2)

The only way to know for sure is to.......... - Chris Garrett 09:59:55 02/16/03 (1)

Re: The only way to know for sure is to.......... - feet's too big 16:49:57 02/16/03 (0)

My Ah! warms up within 10 seconds - Sigmund 19:01:57 02/15/03 (0)

Follow Ups

The only way to know for sure is to.......... - Chris Garrett 09:59:55 02/16/03 (1)

Re: The only way to know for sure is to.......... - feet's too big 16:49:57 02/16/03 (0)

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