Thanks for the advice, Ritz. I will probably do so, at least not taking the next step to a 7.1 until I have a better HT by finishing the basement. At the moment now, my system though not bad but is in the restricted environment of family room (14x14), the sweet spot actually is almost same line with the surround speakers, I probably won't see much improvement by adding 2 more channels. I simply lost my confidence with Adcom after the preamp GTP750 failed recently. I wasn't the only one, my friend bought the same Adcom separates at the same time with me also have the 750 died with same situation (hangup after turn on a little while). Thanks again.
RW