"So do you think buying a decent pre amp is a better option than new speakers? Any suggestions of pre amp that would work well with Rotel and Oppo?"
A decent preamp, no. A good preamp, then yes. Some good options (used): Ayre K5, CJ Premier 18, VTL 2.5, BAT 3.
A decent preamp, no. A good preamp, then yes. Some good options (used): Ayre K5, CJ Premier 18, VTL 2.5, BAT 3.