Any real good system needs to warm up for an hour or two before sounding best. I deal with it by playing digital...then I switch to analog.
Seems like the best "upgrade" for tube amps....
...is to leave the amps on for a few hours before playing. I've noticed recently that when I turn on my Joule amps and let them run for hours, it makes a huge difference in the dynamics and high end sweetness. It gets hot in our house, but it's worth it. Is there a technical reason for this?