"Re: should you leave your equipment on when you're not listening? "
We just got our new Ultra 350 yesterday. The vintage Omega3 and Feltvavle preamp had been playing all day. When we put the new amp online the difference was immediately noticeable and not subtle. More resolution, 3D-holographic imaging, smooooth sound yet with impact when called for. All from a cold start.
I looked through the ventilation slots to see if the platinum Johnson rods were spinning, but I didn't see them. Frank, maybe you could lend a hand....

Did it improve over time? The answer is, 'I'm not sure.' It was a short listening session and we did not have time for a good survey of music. The weekend is at hand so plenty of time to investigate. Next week or shortly thereafter the new preamp shows up.
G E