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Is it a OK to leave tube pre-amps powede up 24/7

I’m relatively new to tubes in my hifi setup. Recently went from SS pre to tube ARC pre-amp and a Croft phono stage.

I have always kept all of my SS gear powered up 24/7(and still do), but I shut down my pre-amp and phono stage now after I am done listening for the day. I power them up at least a half of an hour before I put anything into play.

I would prefer to leave my tube gear on all the time, but am concerned about premature tube wear.

What would the tube folk here think about 24/7?

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danabunner
12 posts
 
Don’t have much to add here, as about everything has been said!

For me, I turn off all of my tube gear (4 power amps and 3 preamps) when I don’t plan to listen to it within the next 2 hours. To my ears, all of my tube gear sounds great within 10-15 minutes of powering on. Some say an hour, I just don’t hear any difference of 15 minutes of warm up vs 60 minutes. The temps inside the tubes are pretty warm within 15 minutes.

I do know a guy who runs his preamps 24x7 and has for about 10 years now. Over 150,000 hours on his tubes and they still test as very good. I also know people with tube preamps from the 60s which still have their original tube sets in them - not run night & day for 50 years, but used a lot along the way - and powered on and off thousands of times. Some tubes do have very long lives!

Personally, I've never had a preamp tube burn out so I don't know how long they last.
rvpiano's avatar
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rvpiano
2,667 posts
 
I've notice even if I leave my pre-amp on all day, it takes about 30 minutes of playing music (especially the phono side) before it really kicks in.
I see no point  in leaving it on all day now
hifiman5's avatar
hifiman5
1,832 posts
 
After looking over this entire thread, it appears that the approach to this conundrum varies based on the preamp you have.  Different circuit topologies must be kinder or less kind to the tubes when left on 24/7. Vive la difference!

glassandlight's avatar
glassandlight
19 posts
 

According to the Department of Defense, a preamp tube meaning a small signal tube if played 24/7/365 will last about 22 years.  At 8 hours a day, over 60 years.

It has been pointed out that temperature plays a roll here.  It is not the tube that is in danger, but the other components.  Heat kills capacitors (especially if your unit has 85c devices not 105c) film exception, and can weaken resistors even metal film ( wirewound the exception).  The reason a 'designer' has suggested you leave something on is for thermal stability....everywhere has the same temperature, no cold/hot spots inside the device.  Hot, cold, hot, cold also weakens or cracks solder joints.

All this applies to preamps.  It still is a personal choice and how big your wallet is.

Power amps....no, no, no...period.  Even 15 minutes is enough to get the temperature of the plates up to operational levels.  Leaving a tube power amp on when you are not listening to music, is money in the bank for tube sellers.  DOD rates power tubes at 3,000 to 5,000 depending how close to class A they are driven/biased from AB, and in class A the hours drop fast.  This applies even in stand by.

Last, if you have a 'stand by' position for the amp, use it for the warm up as it keeps the B+ off the plates until temp is reached. 

geoffkait's avatar
geoffkait
23,365 posts
 
glassandlight
Defense, a preamp tube meaning a small signal tube if played 24/7/365 will last about 22 years. At 8 hours a day, over 60 years.

I'm sure. 😛
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