Can you do anything to make power tubes last longer ?

Balanced power supply. It provides exactly 120 volts at exactly 60 Hz...constantly.

IMO critically important to provide to tube amps...well, if you want your tube amp(s) to sound as it/they were designed to sound, which, sanity indicates you should. Oh, and bias holds better which increases tube performance and longevity,...huh, so I guess the more accurate sound is just a bonus to the longer tube life...funny how that works...

gs5556, how do I check heater voltages ?

oddiofyl, I could have a second system too with my old SS amp but I just wouldn't listen to it !

Those new EL34 Mullards, are they new reissues or vintage ?

  I have always been told turning amps on for short periods then off is bad for tubes. 

I would think that repetition would be the key to avoid on this one.  

Check the heater voltages. If they are above spec, the tubes will fade a lot quicker. Most of the time this is due to high wall voltage above 120V (or 240V) so you can't do much about that other than a transformer. If the wall power is okay then the amp should be serviced. Anything above 6.3 or 12.6 volts on the heaters is either careless designing or fading components. You don't want to stick expensive NOS tubes under those conditions.

I make my tubes last longer by turning my second system on.  I'm fortunate to have a solid state system that I use 75 % of the time.   I have always been told turning amps on for short periods then off is bad for tubes. 

I do bias right at or a little shy of amp mfg specs.   I don't think it's good to under bias either so if it says 53 ma that's where I usually put it.  I use this

https://www.vhtamp.com/avtttt2

Great way to know where you are at.   

For me my best bet is to buy matched quads or pairs depending on application from a trusted seller.   I seem to have much better luck and durability 

Some tubes just last long , some don't.   I have a quad of Gold Lion KT88 that I keep as a spare.  They have a ridiculous amount of hours.   They look nasty, getter is fading , silkscreen is gone.   They test strong still, not far from min new and still sound good.    

On the other hand I had a quad of new Mullard el34.   Did not have then matched / tested and within a month I had one burn up.   

So to answer the question, not much you can do but enjoy and not leave em powered up when you're not listening  

Some amps are designed to drive tubes hard, some will drive tues so gently that they last forever.  Generally I have owned amps by designers who don't run tubes hard and I've had very few tubes fail.  I've been running 80 and 100 year old tubes lately and still haven't had one fail.  I often have my amp on most every hour I'm home.  I use it for music and also for powering the front speakers during TV/movies.   

If you're having tube failures, I'd look at my amp design.

Jerry

1： do not turning on and off repeatedly 

2:   well-ventilated spot

Lower voltage..

I use PS Audio regenerator that outputs 120V constantly, if you believe it.

But I noticed that, yes, input voltage is sometimes above that but never 125V.

Be sure you know what you are doing in setting bias on the low side.  If the measurement is in mA, the lower number means running the tube more gently.  If the bias is in mV, a higher number means lower current and gentler treatment of the tubes.

Thanks for that, @larryi ; I was not aware.  I had read some stuff on bias before that had me confused.  However, my amp is biased using mA and I do run it a bit low.  

Be sure you know what you are doing in setting bias on the low side.  If the measurement is in mA, the lower number means running the tube more gently.  If the bias is in mV, a higher number means lower current and gentler treatment of the tubes.

Be sure the voltage at your outlet is not too high.  I’ve seen 125 volts and higher from some outlets.  A variac, or even better, a stepdown transformer, can lower the voltage to something like 115 volts or lower.  Running tubes at, or slightly lower than recommended greatly improves life of tubes.

Yes, bias is adjusted individually for each tube, and I follow the manual. There is no range stated, there is a black dot you aligned the needle with, that's all.

This may not apply to your setup, but I have individual bias pots for each output tube. There’s a recommended bias range for each tube type . Running the bias toward the lower end of the bias range can supposedly get more life from them. It’s possible that the tube that runs at the lowest bias setting may last longer in general, but don’t know for sure. There’s no guarantee you’ll have optimal SQ with all bias ranges either, but that’s always subjective anyway.

I wouldn't replace expensive and hard to get tubes unless they do something audibly/visibly wrong. But if you use new productions tubes, yeah, why not ?

I suspect you already had it. Don't leave on and less cycles. My  understanding is that tubes become less reliable... as in more likely to blow as well as have the sound quality slowly deteriorate. This is enough for me to change at recommended intervals. Three thousand hours takes a while even at the 2 - 3 hours a day, which I use mine. 

Oh no, I never leave it on when I am not in the house, or overnight, for that matter.

Though my VAC has some circuit that shuts it down if power tube runs away.

I use a variable speed cabinet fan at the lowest speed to pull heat out of my ARC preamp. Can't hear it and it certainly does not hurt. Of course, no data to say the tube life is being extended.

But, I only use the system an hour here and there during the week. 

And fewer on/off cycles, I suppose ?

I think that there may be differing opinions on that, @inna . Personally, I do not like to leave output tubes idling when I am not around/in the close by vicinity. The older I get the more neurotic I get.

But the way I listen these days in only once or twice a day . . . it’s ot like I am in and out and turning music on & off. I will say, however, that even back in those days I never left tubes on when I was out of the house.

But: the sort of exception was with my first tube amp before I knew anything at all of what I was doing. It was (and I still own it) a Cary SLA 70 signature and it has a standby switch. With the standby switch in ’on’ the tube filaments are constantly being heated. I’d have to get into the manual to tell you exactly which filaments are heated and glowing, as tubes and electricity is not second nature to me. Anyway, as I was learning the hard way basic stuff that every tube owner should know, I was talking to the service rep guy from Cary (this is back in the ’90s when they had great customer service) and he said it was not his advice to always leave the amp in stand by as I had been doing. Therefore, I then started using the standby switch in sort of a sequence . . . in other words first go to standby for a while before I went to ’ON.’

As far as preamp tubes, I don’t leave my pre on when I am not listening, either, but there have been threads on that subject, and I know that there are some that do.

And fewer on/off cycles, I suppose ?

I would THINK (and I may be wrong) that if the suggested bias parameter is given as a value between settings, setting to the lower end might be healthier for the tubes. In other words, as an example, if the suggested bias was given as something like 240 mA to 300 mA going towards the 240 mA end of the deal might be easier on the tubes. But I do not know that for sure.

Also to make sure that they have plenty of ventilation.  I suppose one could even set up a small fan.

And if there is a sequence to 'soft start' them for your amp, to always adhere to that.