Amp — Leave on or turn off

By all means, keep your equipment on 24/7.  Everything will sound better that way..  

Remember that recording studios and broadcast stations keep everything they have on 24/7 so they'll aways be able to get the maximum performance from it whenever they need it.  This includes the remote trucks too. And as pointed out, some equipment is designed for it, or requires it, such as class-a and tube equipment, and power conditioners and UPSes.

If you power your equipment on and off it really won't be ready to give you the sound you appreciate sometimes for days after you turn it on, and you really don't spend that much money doing it.  And I've found that my equipment lasts so much longer.

I have 6 amps (Anthem, Denon, Sony), 5 Sonos Connects, a Parasound AM/FM  tuner, a DAC, a Teac cd recorder, an Arcom cd player, a Revox RtoR, and a Carver preamp that are all on 24/7.  Some of them are plugged into sine-wave UPSes, and my main stereo stack is on a Furman power conditioner.  Everything is on 24/7. 

I also have a home data center with 4 servers, 2 switches, a router, 4 desktop boxes, and a wide-screen monitor,  These are also on 24/7.  

All told I figured out this costs me around $50 per month.

I turn nearly all of my electronics off after listening.  The only thing left on is the internet-modem/router.  After powering up for listening, consistently the music sounds better after at least 1-hour of warmup. I'm not certain which components need that hour of warmup however some of my best listening happens in the evening and after the system's been running for hours before.  Many of you I'd bet experience the same thing.  My preamp has no easy to reach power switch and the mfg. says to leave it on unless you're not using the system for an extended period, however I shut it down.  All of my amps are class-A so leaving them on 24/7 is not an option I choose.  I've never left equipment on past my listening time unless it's purely by accident.  And while I can't comment on improvements in sound over longer periods of time with equipment left on, I think it's whatever you feel/hear from doing it that should be your guide.  

My amps run at 100 watts each at idle which comes in at almost $12 a month. I definitely hear the sonic difference running them 24/7. I listen to music mostly over the weekends, so I power up my amps Thursday night.

This is the language in the manual for my Creek amp:

"It is appreciated by Hi-Fi enthusiasts that leaving equipment powered up continuously can Improve the performance. However, this small improvement in sound quality comes at the Expense of continuous power consumption from the mains, which will increase your electricity bill and also reduced working life of the product. The 100A draws approximately 20 Watts Of power when switched on and not producing a signal.

We recommend switching the 100A off at the front panel if it’s not going to be used for a Prolonged period of time. Normal performance is achieved in a very short period of time due To the advanced circuitry in the 100A amplifier."

I just leave it on 24/7. 

I usually leave the amps on most of the day, but I do turn them off late in the evening. With the high price of energy these days I need to be aware.

ozzy