My 990 and 7700 can accomodate 7 channels. I plan on installing a set of rear surrounds by Xmas. Will the 990 rencode anything to 6.1 or 7.1 from my HDA2 or from my Sony 400 DVD changer?

I am running optical out on both, and I am running analog outs (6 channels) from my Sony DVD Changer for SACD.

Since the HD-A2 lacks multichannel analog output, 990 owners such as us are going to be using optical output from the HD-A2. One nice capability of the 990's PLIIx implementation is the ability to overlay PLIIx onto DTS 5.1 sources. This means that when the HD-A2 spits out its high-bitrate DTS re-encode of DD+ and TrueHD sources, the 990 can use PLIIx or NEO:6 to generate back surround signals. So the short answer is "yes" - you can get rear surrounds from any digital input you throw at the 990, up to and incuding the HD-A2's optical output, using either PLIIx, NEO:6, Dolby EX, or DTS ES.

The 990 does not apply any matrix surround processing (PLIIx, NEO:6, etc.) to the multichannel analog input. The only way to get rear surrounds with the SACD output of your Sony changer is to split the surround signals and pipe those signals to both the side and rear surround inputs of your 7.1 Direct input. This was a common practice among early adopters of HD-DVD and Blu-ray last year, but I never tried it myself to decide if it was worthwhile for SACD or not. It'll depend to a large degree on your speaker layout and room - in some cases it may help, but in others it may be of no benefit.

Thanks Gonk.

I still have not hasd the time to run my new A2 to the 990 using a hdmi-dvi cable. I should be getting Bourne Identity tommorow from blockbuster, and I hear the PQ onthat disc is great, so I will have to to it tommorow and see if I notice any difference.

Speaking of HD-DVD's and picture quality, I'll say that I was surprised by Transformers. I Netflix'ed it a week or two ago, and after going into it with no expectations (well, actually, no good expectations) I ended up enjoying it. It had a full dose of cheesiness (giant robots trying to hide in someone's back yard pretty much doomed to such), but it was also pretty fun - and the picture quality was excellent.

I just watched Transformers as well (with the HDA2 going directly to my Sony 60" via HDMI).

WOW!

Actually the HD-A1, XA1, and the 360 Add-on are the only ones that transcode Dolby Plus and TrueHD to DTS via optical/coaxial. All other units downconvert those two Dolby options to 640kbps standard Dolby Digital.

No, the HD-A2 and HD-XA2 also use DTS - it was only the latest generation (HD-A3 and its siblings) that changed to Dolby Digital. At the very least, my HD-A2 pushes DTS to my Model 990 when playing DD+ and TrueHD tracks...