When to power off a tube amp?

For my Bellari headphone amp I just leave it on all the time. Since it only uses 1 12AX7 tube I don't really mind if that tubes gets worn down since I have so many. For my Jolida 502P I turn it on and when all the EZ Bias lights turn red I'm ready to listen to music. For my other Response Audio tube monoblocks I leave it on for 45 to an hour first before listening. When I'm done I turn them all off.

FWIW for those unaware, the Lyr is a dedicated hybrid headphone amp, the tubes in it do not provide power per se. Most all of the 'dire' consequences of leaving tube power units on unattended just don't exist for this kind of unit, any more than they would for a full sized hybrid power amp, integrated or otherwise.

12-26-13: Bifwynne
Al, can I assume, therefore, if one leaves their amp on unattended for even a short period of time, they could learn upon resuming their listening session that not only does their amp not work, they may be minus one or two speakers as well?? Al, there is obviously no written rule out there that I am aware of, ... but at the risk of too quick a turn-off/turn-on, what's your rule of thumb about leaving a tube amp on unattended?

Hi Bruce,

As you realize, the basic point behind my earlier post is that when a tube component, especially an amp, is left on unattended for significant periods of time, in addition to the very small (but non-zero) possibility of fire (which always seems to get mentioned in this kind of discussion), there is also the presumably much greater (but less often mentioned) possibility that a minor failure of a tube or other part will result in major damage to the equipment, if not discovered promptly.

As the experience I cited illustrates, that can even happen as a result of a problem with a small signal tube, especially if the small signal tube is in a power amp or integrated amp.

It seems clear that a case that is at least somewhat reasonable can be made on all sides of these questions, but FWIW my own practice is that the only equipment I leave on unattended are solid state components having no power switch (which are therefore presumably designed with the expectation that they will be left on all the time), and my solid state CDP.

Regarding your mention of the possible risks of turning on too soon after turning off, I second Larry's comment. I can't base that on personal experience, though, as I've always allowed at least a couple of minutes, and usually more, between those actions. Intuitively it just seems to me to not be good practice to do otherwise.

Best,
-- Al

Well apparently turning on the amp is what decreases the life of the tubes? Does it decrease the life more than just leaving it on for that hour of absence? I really want to know as I am buying some Amperex pinched waists 6922 with D-getters which are considered the rarest tube in the 6dj8 family and they are not cheap... So I need to prolong their life as long as possible.

Also, if I don't let the tubes warm up before use, what happens? Decrease in tube life or does it just sound bad?

I own a Lyr and love it although it's had about 8 hours of use since it was new. I let it warm up for about 3-5 minutes. You can't hurt the tubes by listening immediately. If I'm getting up to prepare dinner and plan to continue listening later it stays on. If I'm not going to listen for another hour and a half I shut it off.

I personally would not run this headphone amp with extremely expensive and rare tubes. I'd do that with say a high end all tube unit, but not the Lyr. No reason other than why spend half of what the unit costs on tubes? I'm sure there's plenty of great sounding tubes that aren't as rare or expensive. I still run stock only because I barely use the Lyr to justify owning it.