I never thought that I would end up with an all "Meridian" front end, but after I owned the 508&504 I wanted to control the system with the same remote. I liked the fact that I could also have dual mono between the cd,the preamp,and the amplifier. I bought the preamp first which I ran with a 4Bryston 250 watt amp. Sounded very good, but I was not satisfied, especially since I had moved the equiptment into a larger space. I bit the bullet on the dual mono 557 and ran RCA cables and was getting a bigger sound, but when I finally plugged the XLR cables, what a difference. The whole presentation came up front and center. The Thiel 2.3's, which I thought would be too revealing in the highs seemed to break in all over again. The whole system is never tireing to listen to and all my music sounds perfect to my ear. I really could not be happier. I believe the two major differences that brought the system to it"s present "perfect" state are- Dual Mono and the High Current Amp to push the 4 ohm Thiels, those two items opened up the speakers. My next project is power conditioning and power cords. Any Ideas out there?