From Pass X250,5 to 350,5 : what to expect?

The design differences between and the X.5 and XA.5 are quite "drastic". And pure Class A watts are not the same as A/B watts - in part because there is more to power and sound levels than just watts. By the way, Ayre is also first-class SS amplification - can't wrong with them either.

With all that being said, I would still recommend the XA60.5 or the XA100.5 depending on budget and need for the pure clase A sound versus the A/B. With the Wilsons, again because they go down to 4 ohms I recommended the XA.5 series b/c they can double power. There are times when the ability for an amplifier to provide more power can be significantly appreciated. Even though by the calculation the needed watts to acheive a spl are low, having more watts does offer more headroom and this comes across as control and dynamic differences. Thus the recc for the XA.5s that double down.

The X series also doubles power, always has. But the XA is a better sounding design if sufficient power. The XA100.5 is wat more than enough power with the Revels for 99.99% of the time is most rooms.