I agree with soix on the pre/pro "premp section" argument. I also agree with many others that small tweaks in your system will help (such as placement, etc.) I also see that you've covered the idea that front 3 speakers need to match as closely as possible. However, I think that there are definitely a couple things on your equipment that you should know:
- The Marantz AV-7005 is very nice because Marantz uses discrete analog stages. However, the 7005 uses the older version of the HDAM discrete analog circuits. These have slow slew rates and are much warmer/slower and laid back. The result can be sound that is too warm/slow that does not have enough attack/detail. If you feel you are lacking attack/detail/resolution, maybe look at a newer Marantz. The AV7702 is the cheapest pre/pro that has the new HDAM circuits.
- Soix's idea of adding a high end 2-channel preamp is a good one if you don't care much about home theater and ALSO have different sources you listen to (such as an external DAC). If you use the Marantz AV7005 as a DAC, then adding a preamp won't give you much because you are still dependent on the Marantz for DAC/source. It would be much better to upgrade the Marantz 7005 is this case.
- It's great that you removed the RKB-650 distribution amp and the bi-amp configuration. The RMB-1565 is going to be better. However, it is Class D with a smallish power supply and it is my opinion that this amp sound rather flat and sterile. If you really don't care much about home theater (which it sounds like), then the Parasound A21 comes to mind. It is going to have much more punch, depth of soundstage, air and resolution than the Rotel RMB amp. If you do want home theater quality, it looks like there is a 3 channel Parasound A31 on audiogon for $2100 (which is just above your threshold).
