Well, I received my 770 last week and was waiting desperately for my 990 to arrive so I could start hooking everything up. First impressions of the 990 physically is, MY GOD it's BIG! It's larger than my 770 which is saying something (not heavier though )

My previous setup was a Denon 3800 (only Dolby Digital, no DTS) which is probably 8 years old. The difference in sound is very noticeable. I had hooked my Denon to the 770 to get an idea of what difference just the amplification made and I can say that it made a HUGE difference in the Bass. My Speakers are NHT 2.4T's with bi-wire/bi-amp connections and a built in 10" sub, together with the matching center and surrounds. With the Denon, the bass was loose, flabby and generally horrible. I basically tolerated it for Movies, but it made listening to music impossible. With the 770 ALONE, there was an immediate tightening of the bass. The notes became more distinct from each other as opposed to just a general booming sound. The soundstage which had been indistinct and very small, has all of a sudden grown in size, I feel like the music/movies are around me and vocals are definitely more narural. I have Bi-amped the 2.4t fronts with the 770 and it really helps with tightening everything up. I Did the same thing with my Denon (which has specific terminals on the back labeled Bi-amp - good for Denon) and noticed a distinct improvement in the bass even then. I suspect that the extra power and current from the 770 just drives the speakers way better than the Denon did.

I am adding the 990 tonight and will be tweaking it. I will let you guys know what I think of it once I have been able to listen for a day or two.

Thanks to this forum for all the great discussions and for keeping things smart and sane (unlike some other forums)