Do you always keep the Amplifier powered on

My espresso is about 1500W for 20min (minimum to warmup machine) making 0.5kWh per day (for just one coffee) while my amp and the DAC take together 20W for 24hrs = 0.48kWh. Landscape lighting takes much more, not to mention driving SUV, watching plasma TV or listening to class A amplifier. The most energy wasteful thing you can do is having a child. How many do you really need - one should be enough. :)

Overpopulation is sad and it's likely too late to turn the ruination of the planet around, so I've changed my stand on this issue and say LEAVE IT ALL ON as it no longer matters. Sort of sets you free doesn't it?

No. I kept my Boulder 1060 powered on when I was home on the weekend & found the amp was 95+% warmed up after 2hrs (ie: good enough), otherwise I left the amp on standby. With my current Vitus SIA-025. I find myself in agreeance with Chris Thomas's comments in his Hifi+ review -

"From stand-by, straight into class A I would say that you are looking at a half hour before it really begins to sing and then it just seems to keep getting better. Even after a solid afternoon and evening's listening I would swear that the amplifier was growing more fluid, textural and resolute with better dynamic contrasts, tonal shading and the delicacy of its musical message just seems to become more profound."

To summarize, there are no hard and fast rules. The benefits of keeping a (solid state) amp switched on all or most of the time vary from amp to amp. But rule of thumb, large amps with oversize power supplies and filter banks will generally benefit more from being left on as it takes the psu's longer to warm up and reach optimal thermal conditions.

I have 4 2 from each wife-). I have a similar to Kijanki situation with only 20...30w of idle power for preamp/preamp/PC. No biggie to keep it on while home, but would completely unplug from the wall together with power conditioner the whole rig. Sometimes I have to shut down dac/preamp in order to reset and than turn it back on after one minute and it sounds much better.

BEl Canto ref1000m Class D amps (very efficient) - yes

TAD Hibachi monoblocks (less efficient) sometimes but not always