I have just bought a Marantz SR 4300 A/V receiver (half retail, i couldn't say no) I have it connected to 4 by Celestian CX-2012 (1968 vintage, 12 inch coaxial), a Kenwood 50 W sub and a couple of Denon bookshelves for the back and centre. I can turn it up full without any distortion at all, the clarity is amazing. Since i am primarily interested in music and would like to drive these things a bit harder (the neighbours love it) i would like to know what to do with the pre-amp jacks? Will an amp connected to these boost the power while retaining sound quality and what sort of amp? Under $600 AUS if possible. Any other suggestions welcomed as its only a week since i went from 2 speakers to 6.