Class A vs AB

This link might provide some context.

I would be mostly concerned that my amp would sufficiently deliver the power so that I could easily listen at the levels I want.  As @hjdca said, you could give it a try.  There is nothing wrong with the sound of a good Class AB amp and your amp was meant to cross seamlessly into AB as needed.

You’ve got some really good speakers, so I think the much bigger question is why you’re considering the 1528s? The amp crossing to AB is a relative rounding error here IMO, and by far the biggest variable is the sonic character differences between the speakers and which is more to your liking. 

I have owned a couple of AB Pass amps. The most recent an X350, I could never tell when it switched. 

What musicians do you listen to?  I listen to a variety of music and not much of what I consider rock is a high quality recording. Some of it is.  I'm listening to Riverside currently and it's pretty good. 

I agree that it is more than class A vs class AB. There seems to be so much more to NP designs, such as circuit topology, simplicity of of amplification stages, and types of amplification devices, that factor into the design philosophy and resulting sound. Pass has amplifiers for many different scenarios. The “lower” wattage Pass designs regardless of A vs AB have been known to perform in ways that are not always common to other designs.

I am an XA25 owner with a pair of 4 ohm nominal Dynaudio Heritage Specials at 85db sensitivity. In my room, at my listening levels, the speakers sound great and I am not thinking about A or AB, but about how pure and musical the XA25 is.