How much preamp will improve


I am thinking of adding a preamp to my system. Currently my HT set up include the following equipment:
Audio Refinement Pre2 dsp, Multi 5 amp
Cary 303/200, Nad 541
Harmonic Technology Pro9
Van den Hum d103 mkIII interconect
Spendor S8

I am using the processor as preamp and I have a strong suspicion that it is the limitting factor in my system.

Would my sytem be benefitted with either a dedicated tube or solid state preamp?
andy2
I dump my whole HT setup because I enjoy listen to music more than getting shaked by the pounding from the movies.
I used to have sony 9000ES digital preamp with Bryston 9 BST. The music never as good in HT preamp. The first preamp I jump on was Audio Research SP-11 MKII. Even to this day, SP-11 MKII is still one of the best preamp out there. Another recommendation is Counterpoint SA-5000. This is the bargain in preamp. Very nice and sweet sound like no other preamp and yet it is very transparent and not muddy.
I think you can have the best of two worlds by having a preamp with a HT bypass. It would be a bit cumbersome to operate but I don't mind (having no wife yet :-)).