I owned the XA160 and switched to the XA100.5 and now the XA160.5. I have a difficult speaker load in a small room and don't usually listen beyond peaks of about 95dB with mostly classical music. There is no comparison between the XA and the XA.5. The latter is much better at all volume levels particularly in the handling of and control over lower frequencies. Sense of ease/flow, dynamics and air/space are also better. The XA.5 current delivery and doubling of power as impedance halves are big improvements over the XA model.
These are glorious amps in my system, but they are quite expensive. You should try to arrange a demo in your very large room to see how they sound with your speakers in your system to be sure before you buy.
You could also try asking Kent at Pass Labs or contacting Mark at Reno HIFI if you don't have a local Pass dealer. I have found both gentlemen to be very helpful answering questions.
You can read a more detailed review of my impressions of Pass Class A amps on my Audiogon review of the XA100.5. I am admittedly quite biased as I have owned many of these amps.
These are glorious amps in my system, but they are quite expensive. You should try to arrange a demo in your very large room to see how they sound with your speakers in your system to be sure before you buy.
You could also try asking Kent at Pass Labs or contacting Mark at Reno HIFI if you don't have a local Pass dealer. I have found both gentlemen to be very helpful answering questions.
You can read a more detailed review of my impressions of Pass Class A amps on my Audiogon review of the XA100.5. I am admittedly quite biased as I have owned many of these amps.