When I had my Odyssey Stratos Extreme amp, I left it on for 5 years straight as that was how it was designed and it always sounded great. After 5 years, my wife and I went on a 3 week vacation, so I shut down the amp. Upon return, it took a week for the system to sound good again.
Amplifier warm up
I was plalying Boz Scaggs, "Silk Degrees" LP. After side one, I ate dinner. One hour later I played side 2. The second side sounded clearer, more vibrant with better sound stage. I have a Parasound P6 preamp and Parasound Halo A21+ amp. Is it possible that an hour of warm up improved performance?