Adcom Preamps 565 & 710- Any difference?

I am looking to consolidate all the separate small boxes (i.e., a NAD phono stage, a generic switch box, etc) into one unit. I have a low end Adcom (GFP-350) and an Adcom 5200 amp and want to upgrade the preamp. I keep seeing the 565 (an early 1990's vintage unit, I presume) and the 710 (a later 1990's preamp, also an assumption) on eBay and this site and am interested. What exactly is the difference- in price, in quality, in features? Why does the 565 generally sell for more? Any other preamp in the modest range I should be looking at?
The Adcom GFP-565 was (is) an excellent preamp -- infact, one of the best that Adcom ever made. The 565 got a number of excellent to rave reviews at the time it appeared. Among its best features was a fine phono preamp section. Other Adcom owners of the late 1980's and early 1990's can perhaps share their experiences with the 565, but I was extremely pleased with the one I owned.

During the early 1990's, I had a part-time audio sales job, and Adcom was one of the lines I sold. The 565 preamp earned consistently positive comments from its owners. The 565 still stacks up well against many moderately priced contemporary preamps, which is why it has maintained its resale value.
Thanks for the info. I get the feeling from reading reviews, forum comments, etc that this is a revered edition. Do you know anything about the 710? Is is an updated and better? inferior? unit. If you have a perspective on this, I'd appreciate hearing from you. Thanks.
Thanks sdcampbell. I appreciate your feedback. I bought an Adcom GFP 565 through this site. NMC
I recently bought an Adcom 565 on E-bay for $300. My thinking was the same as yours-one box for line level and phono. It sounds great using the direct outputs (by-passing all tone controls) with all my source inputs. I was considering a new pre-amp from Antique Sound Lab, but ended up going with the SS Adcom. No regrets, this has plenty of inputs to experiment with. I like to A/B different cd players and this makes it easy. The Adcom also has two out-put pairs for use with a sub,another bonus. You can't go wrong with the 565. good luck, Rich. Sorry, I have no experience with the 710.
The GFP-710 is a current Adcom product. It came out a few years ago and is very similar (feature wise) to the 565. It also has a remote control. The Absolute Sound (Neil Gader)did a review on this piece last year
How does the Adcom GFP-565 compare sonically with the top-of-the-line Adcom GFP-750 preamp?
After living with the 565 for almost a year, I can say it is a top notch piece of equipment. I heartily recommend it. My Adcom GFA 5200, however, hums and is underpowered for my multi-speaker listening. I am looking for something more powerful. NMC