Better sounding after 1 hour

Tubes 1 hour; solid state 2 hours.

I leave solid state parts of my system on 24/7 and I can hear a difference if unplugged for a bit to swap something out and then replugged. It really takes a full day to get everything sounding good again, especially toroid transformer gear. That's not scientific, just my experience. Tube gear sounds good after an hour but great after two or three so I turn it on when I walk in the door and then by the end of dinner, listening is wonderful.

My tube amp (and everything else) are on initially for background music so it's generally plenty warmed up for active listening. Leaving SS stuff on all the time is utterly wasteful and to admit doing that these days is kinda lame.

Yes, music from equipment does sound much better if it is allowed to warm up for a substantial period of time. The length is totally up to the specific person's taste. For me 30 minutes to an hour and I am very happy. Quite honestly, for my equipment, after 15 minutes it really doesn't change very much. But, that is just me. You will read many posts from others suggesting how long you should warm up equipment or some suggest leaving it on. If your equipment is solid state and isn't class A, whereby I mean that it would idle with no input at full current bias, then leave it on. It won't hurt it. If, however, the amps are full class A, then you are shortening the life of the electronics greatly because of heat. So, I would suggest turning that piece of equipment off, unless it has a standby mode that reduces idle current to a minimum. If you have tube equipment, do what the manufacturer suggest. Most manufactures tell you clearly what the warm up period should be for tube equipment and many will warn you that tube life is greatly shortened if left on. That isn't a problem for people that 1) don't care about replacing tubes every few months or 2) can afford to. But for the rest of us, Tubes for my equipment are stupidly expensive and since I have no problem turning my system on about 30 minutes to an hour before I listen, I am good.

You should determine the appropriate warm up time for your equipment based on your particular tastes and go with that.

enjoy

Was told by my Pass dealer that the X250.5 from standby takes 5 minutes to stabilize and one hour to sound it's best, longer if fully shut off. My Portal Panache recommends leaving on 24/7 and has no standby option.