I've owned both the MXR and XA160.5 amps. Obviously both are very good amps. I cannot believe the Pass is having issues with bass and control. I would first look to your speakers and room treatments before discarding your Pass amps.
That being said, I prefer the Ayre amps because I thought it sounded more transparent and dynamic in my system but at this level its splitting hairs.
That being said, I prefer the Ayre amps because I thought it sounded more transparent and dynamic in my system but at this level its splitting hairs.