I have Apogee Centaur Major and for many years used them with Adcom GFA-565 monoblock in bi-wire configuration and 565 preamp. These combo worked very well and I was happy. Then I changed amps for Classe DR 10. The sound completely different - warmer bass extanded and sound much loader I had to decrease my volume for at list half of what I used before. I don't have yet good preamp at the moment but think that I will get Classe and it would improve the sound even better.
Evelyn
Evelyn