break-in time for newish rega planet?

Hi,
recently purchased rega planet 2000 that had been lightly used at the CES according to the seller and is in virtually
new condition. ive been using it as the source in a
headphone system (sennheiser hd 600 and melos sha 1) for
about a week and so far have not gotten acceptable sound.
Im kind of baffled since the reviews and feedback have
been so positive. the new player replaced a 14 year old
phillips player which incredibly sounds better. Is it
a matter of allowing more time for break in or could it be
something else?
Thanks
Phil