Rtn1, from your comments, I assume you don't leave the XA200.5 on 24/7? How long of a warm-up for maximum performance? Have you compare the Bryston 28BSST to your Pass? I heard the 28BSST runs very cool, only requires an hour of warm-up and sounds fantastic.
I had a Krell FPB600 and like the X600.5, a 24 hr warm up is required for maximum performance. I leave it on 24/7 and it was MISERABLE in hot humid summer months.