HOUSEBOAT SYSTEM

Seeking advice for amp/preamp for houseboat. Speakers are Niles Audio OS-25's and CDP is Sony DVPS9000ES. Recognizing current requirements when docked and when trolling the waters, prefer recommendations other than typical car stereo. Primary land system is Levinson #333, #38S, etc., therefore, I'm seeking recommendations that will deliver quality audio reproduction. Thanks in advance.