Decent preamp

I found an amazing bargain on flea-bay. 
 Onkyo p-308.  Amazing preamp, quality, sound, superb piece!
   Love her!

arctikdeth, you're right about the Onykos. I owned the P303 way back in the early eighties. It was my first eye opener to a better world of electronics. Onyko reissued this great preamp called the P3000R. I'd give it a serious look. Joe

Croft IMO is the most bang for the buck in Audio .

Visit your local retailer. He will take into account your room size, your speakers, your listening habits, how you listen, what products make sense for you. I always buy 50% more power as a rule so you can have Dynamic range. This way your electronics breathe easily. Make sure you have lots of ventilation, clean the unit every year completely. Remove all cables and clean the ends. using Dioxit and other similar products will help. 

Just another way to look at all this. When I listen to the identical preamp you already have into a  McIntosh amp with the exact same output as your Aragon 2004 I experience a pretty extraordinary performance on all fronts with exceptional accuracy, clarity and separation. You may possibly be trying to improve the wrong end of your system. Just a thought.