Just a little settle time and break-in.. If they sound "BAD" they shouldn't.
The first 24-48 hours keep an eye on them..
I fire new valves up watch for an hour or so, shut down, reseat the valves and leave it on at least 4 hours usually 8-12. I don't listen to much either.. Just to make sure there is no red plating..
At 24 hours I start listening...