Listening after your entire system was powered off cold for a week+

Yet one more report of 1/2 to hour for better sound on a class A tube integrated. (If house AC isn't on all the better too due to white noise.)@decooney A whole house surge protector is your audio, AC and a raft of other electrical things in your house's new best friend. I also yank plugs... why not be better safe than sorry. A brown out once fried all our ACs and a few other goodies. 

I was gone for a week and when I returned today my system sounded amazing immediately, likely (obviously) because I hadn't heard it for a week. My Pass XA-25 always take an hour or so to sound its best, and I had a new Julian Lage album to enjoy...highly recommended by the way...he has Bill Frisell along on this one.

The soundstage changes dramatically over time with the pass labs 250.8.  But I notice that no matter how long I warm up the system, the system sounds better after 30+ minutes of streaming music. 

We (the company 'us') have left home base behind for a few weeks to 3 months, with an occasional 'speed tour' back with no leisure to listen....

Absence can make one's ears 'shift', imh experience.  Having been stuck listening to everything from jobsite machinery to supermarket music, and the random 'basser' next to in traffic, having one's gear go chilly may not be the main issue in mind or at ear.

Although passages, rifts, and lyrics may be in mind, the experience involved with ones' choice of musical means may seem to have a 'shift' in the comprehension of your personal preferences of medium methods.

It sometimes requires a day or three to 'recall' what you liked (or didn't) about it all.  Bear in mind that I'm referring to longer periods of 'withdrawals' ', as opposed to 3 day weekend jaunts....but your experience likely varies, the way most details do..

Thanks for this last round of replies, you guys read my posts more closely. Thx.

@terry9 may be on to something. Narrowing it down, I now think its my DAC more than anything else in the system. Possibly amps too when dead cold.

• Last three days in a row, system sounded just fine after 1hr warmup - all left plugged in.
• At 3+ hours warmup I do notice a bit more 3-dimensional layering and sound coming from the sides and slightly behind me with this particular all-tube system. Big transformers in amps warm by then!

DAC:

My DAC is a NOS R2R Ladder design with a chip (not resistor type) and a TUBE in the circuit. At first I thought I had a failing tube or something, changed it to my spares. Nope, the prior tube was fine. Not the tube in the dac.

• For some reason if I completely unplug my whole system and everything sort of discharges for longer than a week, its clear I need more (2-4hr+) time for warmup the first re-engagement of the whole system from dead-cold.
• I accept the situation closer to what @terry9 shared above. Now re-learning again my particular DAC may benefit by turning it on for a bit sooner before listening, particularly if the DAC has been unplugged and off for a week+. Seems to benefit with earlier power-on time.  

Back to playing the system daily now. No issues, 1hr warm up is just fine.

Thanks for some of the more helpful replies here. ✅👍