When to power off a tube amp?

If you go out for just an hour or so leave them on. So long as you home insurance is paid up.

Turning off is not so much the problem, it's the turn on that is the tube deteriorator in most amps.
As nearly all of them bring on the heater supply and the HT(high tension) supply immediately. That means the HT hits a cold tube.

In nearly all the tube amps I've built I bought the heaters on first with the main switch and with a 30sec auto delay circuit then the HT was connected automatically. So there wasn't a sudden shock to a cold tube with the HT.

Cheers George

I think you should have told the folks that your Lyr amp is a headphone amp. Knowing this I think that you might have gotten different responses from folks had they known.

FWIW I see no fire hazard. None. The unit supposedly runs 'hot' but that is a relative term.

I see no need to turn off the unit except on a daily basis or after you are through using the unit each day. That way it will rest at least overnight. Small tubes typically have a long life.

I would not use different brands of tubes. Brands sound different and you would have the left channel with a different tone from the right channel if you don't use the same brand & type.

Turn down the volume to minimum when you turn off the unit. That should be enuf.

Re warm up - it doesn't take much time to warm up this type of unit. 5 to 10 minutes should be enough to take off any rough edges. If it takes more you will hear why when you listen. BTW, if you replace or roll tubes, be sure to get tubes tested for low noise.

Hi High roller
Really depends on the types of tubes you have.
I run 300bs, and if I am leaving the house for what I think will be an hour(which is always more) I turn it off.
In contrast, my phono pre has 6dj8s which don't like being turned on and off, so when I flick this unit on, it stays on till I go to bed. I think tubes like 6sn7s could likely be left on 24hrs a day for 5 years before they needed replaced, so again it depends on the tube and its relative characteristics, cost etc.
I think question two is debateable re tube health. I would let the system stabilize(a couple to a few minutes. There is debate re sonic improvements and temperature of components. I don't want to go there since your question was for tube life. Power tubes heat up pretty quick. I also don't think tube amps are generally that fragile. Ie they are designed to be used, not only looked at.
Question 3: I would leave them plugged in and save wear and tear on the plug.

Cheers
Rob

Hopefully Ralph (Atmasphere) or Gary (Hifigeek) will weigh in. My practice, FWIW, is that I will leave my amp on unattended for up to 4 or 5 hours -- never if I am out-of-town.

Seem to recall that it's a bad practice to shut a tube amp off and then restart it unless waiting for at least 5 or 10 minutes. The "wear and tear" of a tube as I understand it is the tube's innards responding to hot and cold, which in turn, causes the innards to expand and contract.

Tube failure also occurs because of arcing. I do not know what user-related factors (if any) cause arcing. I for one would love to hear back from Ralph or Gary.

Bruce

1) Turn it off
2) Don't need to warm up before playing
3) don't need to unplug headphones
4) You can use different brands of the same type tube without harm
Alan