Heard the New Jeff Rowland 302 Power Amp?

Yes, it's the best amp - by far - that I've ever heard. You say you're looking for something warmer sounding, but don't specify what you would be comparing it too. I see that you have a Pass X-250 and don't know that amp. I CAN tell you that the 302 will not be warmer than the X-150 or X-350. Feel free to e-mail me if you want to discuss further.

Ral - My experience is that the Pass amps do not all sound the same (which is true of other manufacturers as well, of course). I believe the X600 to be leaner than the X-150 or X350. Also, please understand when I talk about leaner and warmer, I'm not talking about top-end energy or brightness.
Barrelchief - I owned a Model 10, which some people felt, WITHIN IT'S POWER ENVELOPE, was better than the 12s. In any case, the 302 was/is MUCH better than the 10. They are truly in two different leagues, in my opinion - assuming use in a system of considerable resolution and neutrality.

Ral - I agree with you. The 302 may not appeal to all former Rowland fans, i.e. the ones who liked the generally warm character. I've come to believe that the 302 is not lean, by the way. It seems to me to be extremely neutral (as best I can tell, obviously - we don't know what we don't know).

To answer your questions: the 302 is just better than the 10 in every way. I don't know about the 10 vs the 12. I'm just aware some people felt that way. Maybe the 12 is better only if you need the extra power. And of course there easily could be some people that feel the 12 is better, regardless of power needs.