I've pretty much come to the conclusion that "warm" or "cool" are primarily functions of loudspeakers. If you want warm...find warm loudspeakers (maybe something that allows rolling off highs or boosting mids like the STE Labs Avatar).
I don't believe electronics, whether tube or solid state, are the best way to achieve system warmth.
I don't believe electronics, whether tube or solid state, are the best way to achieve system warmth.