Bel Canto, Nuforce, Acoustic Reality, Channel Is.

I directly compared the Bel Canto, CI 200 and the Ref 9s on my Audio Physic Virgos. After serious auditioning, I bought the Ref 9s for their overall musicality, smooth mids and incredible transparency.
However, I have a tube pre in the system - not sure if you'll get the same results running direct from your Wadia -my guess is you'll miss some of the presence brought to the table by a good tube pre.
Enjoy the music!
James

I would not recommend any of the following you have listed, under your criteria you are looking for a "warm..." natured amp. Of the ones you list none would be classified "warm" IMHO.

If you are seeking the type D amplifier, you should also add to your list the H2o.

Almost all class D type amps pride themselves on linearity, clean power, and neutrality. Thus why I mentioned I wouldn't term any of those you listed as "warm."

The H2o has been reviewed against other amps of this type and found to have the qualities you are seeking over other amps of similar type. You can read this for yourself in the
6moons Review

H2o Audio Website

Good luck on your search!

Actually, I may stand corrected.

I have not heard the Channel Islands yet, and have heard from people whom's opinion I respect they are a decent contender.

Of the others you listed, I stand by my comments. Others I have auditioned prior to my H2o purchase were the Rowland 201's & 501's, Bel Canto Evo 2's... I wouldn't add them to your audition list over the H2o's.