What's the verdict on the Adcom GFA-5802

I think you are perfectly ok with the Adcom preamp upgrade. However, I would find a used McCormack DNA 1 (or Deluxe) to use with it. The 5802, for the short time I owned it some years back, just didn't fair well in the comparison. It's an amp that doesn't offend but it doesn't seem to give you all of the music. I felt its dynamic swings were a little lacking, a little conjested in the mids and the highs weren't exactly what I'd call pristine (of course the McCormack can sound a touch "Tizzy" at times if you don't get the synergy thing going.)
They're a lot of excellent amps out there at good prices. I wouldn't just lock in on any particular one. Do a little research and you'll probably have more long term satisfaction. I do think the GFP 750 is an excellent preamp for the money(especially run passive.) The active side has a tiny touch of that Adcom sound but overall it is excellent.

Gandme, There are many expensive CD players that output higher than the 2v standard. I have had several. With a slightly higher voltage, the sounds ramps up in volume a touch quicker and gives a little illusion of being more dynamic sometimes in comparison to others. Anytime components are compared, the louder one will generally come out on top(talking about system volume.) That is why it is always important to match levels and be on an equal playing field when deciding. It is also extremely hard to make comparisons of components unless they are in the same system side by side. The mind can play tricks when you listen to something here and then compare later to something else down the road. This is why I don't put much faith in reviews or comments unless one has used them in his or her own system. I know it's hard to do this sometimes but it is the only way to have an honest comparison.