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Reliabilty, Keeping Equipment Powered on or off?

I generally keep my system components powered on because the system does not have to "warm-up" when I sit down for a listen. I do know that reliability is usually calculated by POH (power on hours) however this calculation IMHO is a broad brush stroke. I do power down certain components that are not required to be left on to sound their best, such as a Luxman T-117 tuner and Wadia 171i Dock . However, my Krell IA, with the volume turned all the way down runs pretty hot, so hot you can't leave your hand on it. When turning the volume up on the Krell to reproduce the live event sound level, you can fry an egg on it, so I can only guess the Krell was designed to handle this kind of heat? However, back to the other components, such as DAC, SACDP, Headphone Amp, etc. Is keeping everything turned on asking for trouble or is leaving it on best to prevent thermal expansion and contraction which may be detrimental?
grm
stereo5's avatar
stereo5
6,384 posts
 
The manufacturer of my amplifier (Odyssey) recommends the amp stay on at all times unless you won't be using it for months on end.  My Stratos amp has been left on since April 2010 and only turned off for 10 days when we went on a long road trip.  My amp has always worked flawlessly and is never warm when idling or being run hard.
grm OP
149 posts
 
Hi, and thank you!

After digesting the posts above, I will be powering everything down with the exception of the Krell. The Krell sounds best when left on and I do not want to introduce thermal stress on the 24 output devices, i.e, cold to hot, hot to cold, etc. I think for this amp, leaving it on with the output devices "warm" is the best way to treat them?

Thanks to all,
grm
larryi
3,979 posts
 

From the standpoint of safety, longevity and energy savings, it makes sense to power down everything.  This is particularly true of tube gear.  I can understand not wanting to power down amps which can take a really long time to come back up to song, but, these are exposed to the most heat from being left on, and these can do damage to speakers if something happens while you are not there to power them down.  As for thermal cycling, that is really not an issue because it happens relatively slowly.  If you look at rating of most parts, they include rating by operating temperature--the higher the temperature the shorter the life.

I only keep on what is meant to be on all the time.  That means I don't power down my music server/NAS.  It would take about 20 minutes to bring the server network back up if I turned it off (components have to be brought up in a particular sequence).

dhl93449
455 posts
 
One thing not mentioned. Power line transients. The longer something is kept on and connected to the AC power, the more potential for damaging power transients to destroy components in your power supplies. If you have good line voltage protection (like a Furman line voltage filter, for example), then this is less of an issue. But also be apprised that many line voltage protection devices (like MOVs) have a limited number of transients they can absorb before they fail and you have no further protection.

Power brown outs may create similar problems. If you have frequent or constant power line drops, this can also be hard on equipment as it shuts down due to the low voltage then re-powers as the voltage levels are restored. All this may be happening while you are gone and unaware if you leave equipment powered up continuously.
bruceofcleveland
7 posts
 
My Rowland Cadence / Coherence preamp/phono doesn't want to be powered down, in fact there is nothing in the manual about turning it off, ever. Worse, if you power it down, you have to go through a whole blah-blah to start it up again properly, vis-a-vis the batteries in the power supply, and to top it off it forgets where it was. I turn the preamp down to zero, and that supposedly shuts down almost all of the internal circuitry.
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