Looking for warmth

My suggestion would be to sell both amps and the preamp and buy an Onix SP-3 tubed integrated. This piece is warm, sultry and extremely articulate. It opens the door to the big time. You can find one on here for about $500 new or used even though it is built like the $5000 tube gear from the big American names.
The only caveat concerns your listening habits. While the bass from this amp rivals anything solid state, this amp is for music and will not serve well for ear splitting headbanger stuff. Look into it at www.AV123.com

Stop everything. While I like my suggestion, I have to say that Onhwy61 has made the best suggestion of all. He is also the most experienced audiophile to have responded and I would try his methods first because they cost nothing and could well be the answer. It seems unlikely that a guy who is seeking suggestions for a $500 amp upgrade will be substituting a $2000 preamp instead. The people who have been after this grail the longest are usually the ones who provide the least radical remedies...... and vice versa.
It is true that Adcom is not so bad. It may be a bit sterile but it sure won't make your ears bleed.
The reason I recommend the Onix has to do with value. It will move you quite close to state of the art for a pittance.