Not that I use it for music but my new Yamaha RXV1065 AV amp sounded pretty awful at first - I was ready for this though - and it's improving all the time as it runs in. If you're out (well or in I suppose) tomorrow - just let it play all day and I reckon it'll sound totally different by the end of the day.
How are the speakers supported? It never ceases to amaze me how much difference stable speakers make...
Naim CD5i & Nait 5i, Dynaudio Audience 52SE, NAC A5 cable, Atacama SE24 stands, Sony BDP S550 Blu Ray, Yamaha RX-V1065, Panasonic 42" plasma.