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Always turn off tube amps when not in use or near future use. No reason to leave them on they voltage stabilize within mins and with the heaters warm up in 10 mins or less. really not worth the tube wear or power use if not going to be used in the near future. Tube amps have 100's of volts on the plates some are 1000v+ so really do you want that thing on all the time when your not home.
Also don't leave them on when no one is home not really that safe, I've seen tubes self destruct when they fail be nice to be home so you can turn the thing off so not to damage other parts of the amp, or burn your home down. you wouldn't leave your stove on when your not home would you?
I feel its irresponsible to leave equipment on all the time just to say oh I don't like to wait until it warms up. well the planet is warming up so take a few mins to plan ahead when we listen. Turn things on go get a drink hug your spouse your kids what ever then go relax and listen.
if your really savvy get a remote switch to turn them on when your on your way home.
IMO a tube amplifier should never be left unattended. So an hour left on... and no one home. bad. A tube preamp I would say depends on the tubes. (exposed, encased) and how hot the tube preamp gets when on.
I used to leave a 12AX7 12AU7 with 4 tubes, fully enclosed and got only a little warm on 24/7/365. A current Conrad Johnson ACT2 gets really hot when on. plus the tubes are exposed in a plexiglass cage... and I turn that off even if I am going out to the store... half an hour.
I leave all my solid state on 24/7/365
Many tube amps have a stand-by mode in which the output tubes are off but the amp is still warm. My Cary amp have this. When I'm home and know I will be listening that day they stay in standby. When I leave the house or go to bed, everything gets turned off.
I once saw my tube preamp go up in smoke while it was just idling.
I usually shut the amps off each time I am done listening. Whenever I leave them on thinking I am going to go back to listening, my day usually changes so I can't. If I turn them off, the odds of being able to listen more dramatically increases. And, these things get hot-- including heating up the room when you have 8 kt120's per amp x 2, a couple of m8080's and a 6922 in the preamp, and the Sophia's in the CD power supply. 24 tubes total when everything is on-- that's too much electricity to waste if it's not in use. And, finally, I have seen a tube fail-- right in my amp-- spectacular but scary. I want to be around if/when that happens.
The most potential damage to your tubes is turning on your amp. The likelihood of a tube exploding and torching your house are tiny. Some amps will pop a fuse if a tube flares and some don’t. Bias type is most of the question there. I’d be more concerned with being electrocuted frankly. I would turn off after an hour or two of idle. But only once a day. No we regarding tube pre’s leave te=hem on in standby mode except when on vacation. They draw minimal power,the tubes last eons and they stay heated. But remember to pout in standby. Caps, etc go bad first from sitting and second from wear. If you are worried about tube replacement then you should, well...hey it’s part of maintenance. And I’ve been guilty of going out of town leaving a pair of monoblocks on—had to call a friend to go and turn them ooff for me. Fortunately he could get in through my garage with the code. Enjoy!
Just wondering about the 1-2 hour breaks.We have a Standby feature on our amps. It keeps them lit but no B+ on the power tubes (the driver however still has B+ as the 6SN7s have a much longer life). This helps the amp keep its warmed up quality, but no wear on the power tubes.
But if I am away for much longer than that I just shut the amps off. If the amp has no standby feature I would just shut it off if you're only gone for 1-2 hours.
I would think haw many hours a day you listen also matters.
Being retired I listen to music somewhere around 10 to 14 hours a day, every day. For folks still working (not from home) that is impossible. Some folks travel for work, and so have maybe only one day every few weeks to enjoy the stereo/music.
When an output tube blew in my Rogue Cronus Mag. II, a while back, I called Rogue to get advice and order a new set of KT-120s. Rick told me that I could expect to get about 2000 Hrs. from a set of the KT-120s and several thousand from the input tubes. Since I listen to my music for about 40 - 50 Hrs per week that would be a new set of tubes every year - even If I faithfully turn off at the end of every secession. Rick told me that there is no sonic advantage to a warm up of more than 10 or 15 minuets on that amp, so, in lieu of cost and headaches, I'm being a bit more mindful of shutting it down between listening sessions...Jim
My preamp and single ended amp both use 6SN7GTBs and my preferred NOS RCAs and Sylvania "chrome domes" aren't expensive at all (relatively). A NOS Amperex was supplied with my Dennis Had power amp and still sounds great after a couple of years. You can, of course, spend a lot on certain brands, but I won't.