Try one of the cheap Parasound or Acurus pre-amps. They are really dirt cheap and sound very clean, clear, and involving. I know the Parasound sounds silly good for the money. I just bought several of the Acurus R11 pre-amps based on their "underground" reputation as being giant killers - my ears will shortly tell me.
The Audiohorizons 2.0 and 2.1 pre-amps are sold on Audiogon and sound excellent. Air-Tight makes several fine sounding pre-amps. Both of these units will be in the near 2K to 3K range.
Jospeh Chow at Audiohorizons modified a very nice sounding Air Tight for me, even took the power suply out and built a separate box for it. He took a very nice pre-amp and turned it into a STUNNING performer.