I'm more interested in Audio versus video, and may use one of the above in stereo only for a while if I decide to purchase one of them. Is there a difference in sound quality between the 2 of them.

990 is better, but if you intend to use it with small speakers and analog stereo sources, you should be aware of the so called "bass management bug".

If you intend to use it exclusively with digital sources, then 990 is a better choice, not that 970 is a bad one either.

Is the 990 $300 better than the 970 for reproducing digital stereo music, or does it just have $300 more flexibility for surround and video, and the ability to still play anolog.

Forgot to list my current system - I'm new

Adcom GTP-400 ( this is dying which is why I'm here looking around)
Adcom GFA -535
Vanderstein Model 1's
Arcam CD73
Sansui Belt Drive Turntable ( haven't used in years, but wouldn't mind dusting off)

990 has better electronics in the signal path, that's for sure. The $300 difference might come from various directions, marketing included, hard to tell.

And if you're looking at a turntable, then only 990 has a phono input...

Your gear is two cannel, why are you looking at a 7.1 surround processor as a replacement for your stereo preamp? Just curious...

Wait for the next version of the 990.

I'll get into surround sound piece by piece. But I still want the priority to be sound quality. I thought about the receiver, although I hate to replace seperates with a one piece unit. If I get a good sounding pre/pro, eventually I can fill out the system, but also have good quality sound.

Goyangi, I too have a stereo setup right now and will get into surround sound eventually. I also have a turntable which I still use, so anything without a phono input was not an option. And that's why I got a 990, and recommend it to anyone in my position, including you. The quality of the sound is real, real good. And if you're really interested in music, I'd also recommend a tube buffer between the pre and power amps, and the Yaqin is a heck of a buy.
Having said that, I haven't heard the 970 so can't comment on it vs. the 990.

Hello psyprof1...Can you please describe your listening experience with the Yaqin processor? Did you place the Yaqin between your source and the pre amp? Pardon me if you have discussed your experience with the Yaquin processor in another thread.

I just purchased two Grant Fidelity Tube processors...which to my limited knowledge is the same as the Yaqin. Thus, I am curious to your experience.

AK

Sure, akdrama - my Yaqin is between the 990 preamp and Adcom GFA535 power amp - the only place where it can work on all inputs. It's connected to both the preamp and power amp with Kimber PBJ interconnects, not because I've found them to be the best my imported-beer-budget could afford but because they were the best interconnects I had two pairs of. As for the difference it's made to the sound, I haven't tried turning the Yaqin off while playing (at which point it presumably becomes a straight pass-through for the signal) though this is possible. But the impression is that it increases both the "sweetness" and the presence of the sound. Today I was listening to a Dvorak string serenade over an FM station with a good-quality signal and the massed strings, especially the cellos, had more of the woody sound one hears in live performances. And on cable TV news programs (coax digital audio connection from a Scientific Atlanta box to the 990, which does the DAC duty) commentators' voices, especially the men's, sound much more "in-the-room" than they did before. There also SEEMS to be an even better phantom center channel sound from my Magneplanar 1.6QRs, and they were pretty good at that before I installed the Yaqin. I have not yet tried substituting a better tube for the Chinese one that came with the unit, a change which is said to make the highs still better.
Hope this helps. I never heard of your Grant Fidelity units.