05-27-12: Audiofreak32
Warm sound will almost always require tubes...
"Almost always"? I don't think so. Warmth is a tonal balance thing and any number of speakers are voiced this way and speaker placement has a lot to do with it too. If you're talking about smoother highs, there are plenty of SS amps that do that too. Also, some speakers have etched or edgy highs, others have smooth and well dispersed highs.
I have a pair of Mirage M5si's and with their mid-20's bass extension, bipolar radiation pattern, and well-damped titanium dome tweeters they are definitely warm no matter what powers them. I have powered them with Forte, VSP Labs, Carver, and Adcom. The speakers sound warm with all of them.