Dedicated lines- need break in?

Surely a, stupid question of the day!
Finally had 2X 20 amp dedicated lines installed with Oyaide outlets with isolated grounds. Hooked up sources and preamp to the lines to start with......, and sound is much clearer and as a result slightly on thinner side (in comparison, although still anything but analytical). I know it is not Oyaide outlets because I had them connected on regular lines and they sounded warmer. (I have electrician coming back today to try out different phase than the refrigerator, ac, microwave etc. to check if the current in phase circuit breaker is not causing the change in sound)

So the question is, in your experience, the new 20 amp lines need to be broken in? How long does it need to be? or what could be the cause?

Thanks,

Nil