I owned a GFP-750 and it is indeed an outstanding preamp.... But it didn't seem to "separate" the instruments as well as my Audio Research LS16 tube preamp. In comparison, the GFP-750 sounded a little "cluttered" and bright. I know you're not interested in a tube preamp but thought this would be an interesting observation for you.
Like Eric's post above, I too have owned the Classe CP-35 (and CP-45) preamps. Keep in mind there were actually THREE different versions of the entry CP-35 preamp. You can find CP-35's for about $500 to $700 used. The recent versions have full-funtion remotes while the early version controlled only the volume and mute. You might also try their higher up model CP-47.5 for about $1200 to $1400 used. I found the Classe preamps to be a little less "bright" compared to the Adcom GFP-750 and over all more enjoyable.
...Abe
Like Eric's post above, I too have owned the Classe CP-35 (and CP-45) preamps. Keep in mind there were actually THREE different versions of the entry CP-35 preamp. You can find CP-35's for about $500 to $700 used. The recent versions have full-funtion remotes while the early version controlled only the volume and mute. You might also try their higher up model CP-47.5 for about $1200 to $1400 used. I found the Classe preamps to be a little less "bright" compared to the Adcom GFP-750 and over all more enjoyable.
...Abe