Input Impedance for Power Amp

Hi all, I don't quite understand the matching of pre-amp and power amp. Let say if my amp has an input impedance of 10k ohm, what kind of output impedance the pre amp should have. Should it be more than 10k ohm, or less? Can it be a lot less? What if my CD Player(with volume) has an output impedance of 10 Ohm, can I still run it directly to the amp? Thank you for your advice.