CP-45 is one gem of a pre-amp. Cp-50 pales in comparision. Cp-60 is only slightly better in terms of transperancy, but musicality across the full band, CP-45 is more complete package, for a very low price. I have SSP-50, which is CP-50, and I still prefer stereo listening thru CP-45. The word (my dealer)is CP-65, the new one has musicality of CP-45 and transperancy of CP-60 , but then you are talking lot more money.