Looking for suggestions to upgrade my processor

I am using a Parasound 2500u and a 2205A amp running four Hales Revelation 3's and a Revelation center. I love the warm sound of the Hales and the Parasound amp, but would like a little more emphasis on the high frequencies. Any suggestions on a processor that would allow me control the tone, similar to the treble function on a 2 channel preamp? I connect my video, DVD and bluray players directly to the plasma screen, so I don't care about video processing at all, only high quality sound. This is a combined music and home theater system. I primarily listen to jazz, acoustic, and classical music. And I am a big fan of used equipment -- much more bang for the buck. Any suggestions? Thanks