Leaving my amplifier on ok?

My PS Audio amps are designed to be turned off using the front buttons while keeping the circuit warm as long as the back buttons are not turned off. After turning on the front buttons warmup time only takes about 20 minutes.

@bigtwin

Maybe dumb question but do you mean "on" as in ready to operate or in "stand by" mode?

I ask because I typically leave my H390 in stand by mode. If this not recommended, I’d like to know.  

All components have a rated life that includes the life at different operating temperatures.  It is always the case that higher heat means shorter life.  If an amp is run constantly, mostly at idle, I would hope that it is designed such that heat would not be excessive, but, in any case, that heat and constant use would not increase the remaining life.  It is particularly the case that heat as well as constant operation would not be good for transistors.  As for thermal shock affecting PCBs, I have my doubts that normal turn on and off operation would not have a meaningful impact on life of boards, and would be interested in information demonstrating otherwise.  PCBs are tested for thermal shock vulnerability, but testing conditions are quite extreme (like -40 centigrade to 100 centigrade), not the kind of conditions found in home operation.  Boards are expected to last for at least 50 years.

Electrolytic caps do sound their best and are well preserved by being kept charged, so there may be some benefit there to keeping an amp on all of the time.  But, they too are subject to shorter life from higher temperatures, so, some sort of tradeoff/balancing is involved there.  The big issue with leaving electrolytic caps in a discharged state involves many years of storage in such state--it is not really an issue as far as a few days or even months of non-use.  But, sound quality is another matter.  Some gear takes a long time to sound its best even when warmed to full operating temperature because the caps are not fully charged/formed.  For example, NAIM recommends leaving their streamer on all of the time because it takes the caps almost a whole day to be at their best from a cold start.

The other safety/reliability issue has to do with power surges from electrical storms and brownouts that may occur while one is not at home and able to turn off gear.  I have not heard of many instances where gear has failed and caused a fire, but, that too is a (remote) possibility.  

When I ran solid state amps, I kept them on all of the time, except when I left town.  I knew this involved some risk and shortening of the life of the amps, but, I accepted that to avoid a warm up period.  I now run tube gear, which MUST be shut down when not in use to preserve tube life, but then again, tube gear tends to sound quite decent after a relatively short warm up period.  I can enjoy the sound, even if it might not be at its very best, within five minutes of turning on the amp and linestage.

Sorry, to clarify I meant:

Some Class D amps (IcePower especially) BENEFIT from being left on for 2 days or longer before listening,

Thanks to jasonbourne71, and erik_squires for some clarification.

In the old days caps were not nearly as reliable as they are now, so frequent on/off surge cycles were bad.

They are much better now and it's no longer worth keeping an amp on all day, due to the other aging factors.

Some Class D amps (IcePower especially) from being left on for 2 days or longer before listening, but thanks to the efficiency it's not nearly as taxing on your budget or the planet.

And no, no Class A amp should be left on continuously.

Heat kills.  No for class A amps.

@pmm +1! If Class AB they can run 24/7. Power supply caps will stay warm and nicely formed. Class A amps that run hot should be turned off when unused.

Use "search discussions" above, where topic has been discussed, at length.

For solid state amps: best to leave "on", all the time, if you listen frequently. This reduces "thermal cycling" of the circuit board. 

I run Hegel amps and wondered the same thing after reading so many different opinions.  Questioned Hegel directly and was told to turn the amps off when not in use.  They said leaving them on only shortens the life of electrical equipment.  I listen to music every evening and turn the system on about two hours in advance.  

There isn’t a electronic component that has its life extended by being on all of the time.  Amps, in particular, have a shorter life from being left on because of hear.  Tube gear should not be left on because there is a limited life to all tubes and that life is primarily determine by how long the cathode of the tube has to emit electrons.  The only reason to leave something on is to reduce warmup time.