With a $4000 budget, you have a lot of good choices. You might start by considering the Bryston BP-25 preamp and Bryston 4B-ST. Both can be purchased discounted for about $3300. If you are interested, drop me a personal E-mail and I will give you the name of an Internet-based dealer that has good prices. (I have bought several items from him, and he is very prompt and professional.)
If you stick to solid state gear, you should also look at Rotel, Adcom, Aragon, B&K, and Musical Fidelity (sold by the Audio Advisor).
If you stick to solid state gear, you should also look at Rotel, Adcom, Aragon, B&K, and Musical Fidelity (sold by the Audio Advisor).