Which amp matches best my JM Lab Mezzo Utopia ?

The 211s are really an option for me. My concern is that they have only 22w of power. Wouldn't it be better to go for solid state Pass Labs XA 160 - class A 160 watts more so as I use a passive pre?

Sorry, but the XA160 is not single-ended.

I have thought it is parallel single ended very much like the Aleph.

The way I understand it (I guess I have to say I am an electrical engineer), is that the Aleph is truly single-ended but the XA series is, as Pass puts it, "parallel single-ended" which to me is just marketing jargon to fool audiophools into thinking they have a single-ended output stage when in fact, the input is single-ended but differential. Parallel balanced output is not single-ended output. You have to read his website more carefully or just believe it and get an XA160 and be happy!

Arthur

The BAT solid state amps deliver lots of current, so that handles your load requirement, and are biased heavily into Class A. As such, they run hot, but I've owned BAT pre/power for the last seven years with no desire to make a change. Don't know them with the Utopias, but my Magneplanars are 4 ohms nominal, and there's never an issue of drive or control.