Pass Labs XA30.5 and ModWright KWA150

Low maintenance.

I too had the XA30.5 and M60s at the same time driving Merlin VSMs. The Pass is by far the best SS amp I have ever heard. I kept the Atma-sphere M60s, as it was the best amp I have ever heard driving the Merlins. I have not hear the Modwright, so I have nothing to say about it, but I do get the feeling that the XA30.5 will be remembered as one the very best amps Nelson Pass has ever made, and that says alot.

The XA is a bit more tube like compared to th eX series.

Ral, what does "tube-like" mean to you?

A Pass amp that works a bit more like a tube amp, especially in terms of damping AND being a very easy load for the tube preamp would be the First Watt Aleph J if you can find one used. I think it works extremely well with smooth and highish impedance speakers (tube friendly speakers).

I agree, though I have never heard the ZeroFormers with the M60s (don't need them), there is something about the very idea of it that doesn't quite feel right - even if they work.

Because it might still sound great with an autoformer. For instance, it is still a Class A, triode amp. But I do agree with the general idea (not based on any technical knowledge at all)that there is some dissonance in the idea of using an autoformer when you have purposely decided on an OTL amp.

OP, if tubes are out of the question for you, I would go with the Pass XA.5, it really does not get better than that if 30 Class A SS watts is enough to drive your speakers.