Proceed HPA-2.. What preamp to match?

I just moved up from a BPA2 to the HPA2. The HPA is only 1 1/2 yrs old and I am using a Adcom GFP-750 preamp with Dynaudio 1.3SE and Naim CD 3.5 and a Naim flatcap. I have just purchased Acoustic Zen Matrix Ref II balanced IC's for pre amp and AZ Satori speaker cable. Also using 3 Signal Cable PC's. While I only have about 20hrs on the AZ I'm pleased with the warmer/more open sound then the entry level Synergistic Research that I replaced. The Dyns sound much better going from 125 to 250WPC but wanted to ask if I could improve the mid and upper range by looking at another preamp. I really like the Proceed yet feel my system could still sound better. If I replace the Adcom I would be spending @ $2000 for a new or used preamp. I'm in an area where I can't demo a lot of equipment.. Do those of you who have owned Proceed (or even if you haven't) think there would be a better preamp at this price point. (My listening is almost all classical music) Thanks for your help/advice.