Reliabilty, Keeping Equipment Powered on or off?

If they (audio equipments) are designed to handle those conditions, then of course , it should be left on without problems. It's those equipments that use poor quality parts that have "borderline" specifications on heat, current, mechanical tolerance (thermal expansion) etc..  that we should take note of irregardless they are running hot during idle or operating in Class A or not.
regards,
-phil

I've previously noted that leaving things on even at the suggestion of amp designers is the domain of wasteful boneheads who, as an example of wasteful boneheadedness (!), might also leave their cars running at all times to insure proper engine lubrication without that pesky "start up" stress, and leave refrigerator doors open to obviate door hinge wear, etc. I've since completely changed my stance on this issue (although I turn my rig off so I don't have to think about it blowing up when I'm not listening to it) as the rampant wasteful tendencies of people have irretrievably set our demise in motion, so you might as well waste whatever energy you can. After all, your audio playback standards can make you happier, and will help assuage any stress from, for example, an area of African farm land the size of Alaska recently being rendered unusable from rising sea water contamination. Who cares? Get yer Mahler on and you can let the kids worry about all the other stuff...  

There’s no one right answer anymore.

The biggest issue with on/off cycles was the initial current surge that goes through the transformer and power supply capacitors. They are much better now than 40 years ago, and many amp makers have added soft-start circuits which prevents this from occurring.

So the concern for turn-on surges is less than it was historically and leaving your devices on 24/7 has a down side. All power supply capacitors are rated for a certain number of operating hours so even while you are away you are running the clock down on them.

The higher temperature caps a vendor used, the longer they will last in general.

The other thing to consider is AC surges and spikes. Depending on where you live, like say Florida, these can really wear down the caps quickly. Of course, you also run the issue of a power surge happening when you are away.

So, I’d say keep your low power equipment turned off unless you have a good surge supressor. Then leave them on all the time. :)

As for big items like the Krell’s and tube power amps, I have a tough time stomaching the damage to the environment I’d be causing. If they are relatively recent models, I wouldn’t be surprised if they already had built in soft-start circuits as well as more modern caps that are less vulnerable.

Personally I’m off in class D land so for a total of 15 Watts at idle I leave my stereo amps all the time through a Furman surge protector. :) The amps are also excessively well cooled, so the wear and tear on them operating 24/7 is much less than your Krells I'm afraid.

Best,


Erik

That Krell worries me....why don't you just call Dan in Cave Creek, Arizona and ask him.   Its probably pure class A, but still.....heat is a destroyer.

All my gear is in stand by or full power 24/7 if it does not have a stand by unless i am away for the night then all gear is powered off. All gear is solid state. I have tried both ways and my sacd/cd player and pre amp all sound better when left on. Was told this by the factory rep better to leave on.