Strategies for preserving tube life

I have a First Sound tube line stage with expensive (and glorious sounding ) Siemens Gold Pin 7308 tubes. I want them to last. My question is, what are the tradeoffs between wearing out the tubes by leaving the pre-amp on vs. stressing them out by powering up and down too often. So, for example, I power down when I leave town for two days. Should I also power down when I leave the house for 4 hours? Or when I go to bed at night? -Dan
I should clarify that my system is on a lot when I am home, and I work out of my house, so I'm home a lot.
This question has been discussed a lot on some sites. Do a search on audioasylum tube forum or the bottlehead forum.

Clearly, Tube life has a lot to do with the voltage running through the filament(or cathode or whatever you want to call it.) Checking that out and adding a Resister if needed)can add life if you are into DIY. The general rule is use the lowest filament voltage to properly operate.

I remember reading a post by Paul Joppa, one of the main brains at the Bottlehead site and he used the figure one hour which he said was accurate to within a factor of 10(for reasons he did not explain). So he apparently thinks the time frame is from 6 minutes (1/10th of and hour) and 10 hours. I guess that means turn it off overnight and when you leave for the day. I'm not smart enough to argue with PJ.

Some folks worry about fire and AC spikes too if you leave it on all the time.

Enjoy the tubes!

The characteristics of the particular tube matters. In my experience, for example, 6922s wear out when left on continuously but good NOS 12AX7 tubes don't. Unless you can find a specific reference to you tube type I would suggest turning it off based on a 6+ hour cyle time. You should also listen carefully to the warm up characteristics. Some tube gear stabilizes in an hour or two and some sounds terrible for the first 4-6 hours. This might not matter if during the day you are casually listening and doing your serious litening in the evening since the tube would have had the whole day to warm up.
No one, as of yet, has come up with a deinitive statement, on whether leaving them on, will make them last longer, or continuously cycling them on, and off, will last longer. The manufacturers, gave a 10,000 hour, minimum service life, for these tubes, but their testing, was based, on always on.
My suggestion is to get some Pearl tube coolers and fit them. Not only have I found that they make the tubes last much longer (I don't know how long, all my small signal tubes are still ok after several years use - I switch my amps off at night), but they seem to help microphonics as well.
Only downside is that you see less of that lovely tube glow, but there is no free lunch!
Does any one else have suggestions for tube rings or socks and do you know if they really work? Tmcroy notes Pearl tube coolers and I know that ARC and Ensemble have some fings and socks? Any comments?


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If I recall rightly our Albert Porter, leaving his Aesthetics front end on all the time, has reported here, that the deterioration of his NOS tubes within the course of one year was minimal. I can come up with the same message, regarding my Jadis PrePre stocked with Tele ECC83s, which still measured good after three years. The same holds good with the stock powersupply tubes. By the way, I've used the Ensemble socks in the Teles. If that did any good, I cannot say.