Looking for warmth

I totally agree with the McCormack amp suggestions. The place to introduce tubes, in my opinion and if you are so inclined, would be at the preamp level.

I have been very satisfied with VAC preamps in that regard. You can pick up a used Standard LE on Agon for about $2K or so and it is an excellent intro to tubes (plus it is built to last forever). I have also discovered a great synergy between VAC and McCormack gear.

Start with the preamp. I would try one of the offerings from conrad-johnson maybe. Both their tube and solid state units go in the direction you want. If that change is not enough, I would do the same then with the power amp. Again, I would suggest conrad-johnson. I would leave the cables and interconnects to the end. I think they have the least effect and should simply be final tweaking, like tone controls.

Get the MF toob buffer, or there is a China made knock off.

It may do the trick, but oooo those Adcoms.
There is a sweeeeeet VAC on here someplace, I just saw it for dirt. I thing 450!!!! That could work as well.

loon

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.

The preamp and amp have to go. I strongly suggest a McCormack amp. Try to get one off the gon that already has some level of revision done to it by SMC. Preamp is hard for me to suggest but I have liked Audio Research for years. Please let us know what you did and I hope one of them is a McCormack amp.