You should let us know your budget. Maybe you could try a used tube preamp? You could always get an Adcom GFP 555II for cheap and it's much better than the gfp1.
What Preamp should I use
I have a Denon POA-1500 with which I am REAL happy. Recently the ADCOM GFP-1 has a problem with one of the channels fading in and out (I enjoy the clarity of ADCOM with the Denon, ES Sony CD, and the Snells speakers) but it is time to get a new PREAMP and I do not know what would be comparable with the set-up I have now. Can some one help me with this and I do not know of