I agree, low volumes are fine. As long as there's a signal. BTW, be sure to cut the amp off for long enough for it to cool and then fire it back up. This will allow the amp to cycle through cooling and heating up which will help speed the process up.
Amp burn-in..Best technique
I will soon be getting my new Mcintosh MC591's. I am curious,......does it matter how loud you play? If I run a CD on continuous repeat,...does it matter if I turn it way down? Or does that not offer enough resistance/load to drive to have a "break-in" effect. My wife would not be happy if I had my system playing at high levels all day.