if it’s about showing a system off, the worst thing is to ask for a suggestion. most people, especially those not accustomed to higher performance audio, don’t understand the disadvantages to a poorly recorded track. shortcomings that are masked by cheap earbuds or bluetooth speakers show up in a better system. if I am showing off a system, I have several tracks I use to do so. after that, I will take suggestions.
amplifiers warm up relatively fast. I do not leave mine on (plus it uses vacuum tubes). DACs I always leave on. digital takes a lot longer to settle and sound right.