Sophia II's and Pass Labs etc

Hce4, could you elaborate as to why Pass Lab prefers the XA30.5 or XA100.5, while discourages you from getting the XA 60.5? Thank you.

Hce4: thank you very much for that great post. Interesting to hear that you found the XA 30.5 sweeter.

I'm auditioning the XP-20 now.

Spatine,

Kent at Pass Labs mentioned that on my speakers, the XA30.5 and XA60.5 would perform quite similarly with the main difference in power and current. Kent made the point that the XA60.5s would outperform the XA30.5 at high volumes (100db+), while at normal listening levels there would be little difference. Kent mentioned that the XA60.5 are basically monoblock versions of the XA30.5 and were produced for people who desire monoblocks. He strongly thought the XA30.5 would be more than adequate for the Sophia II's, and the XA60.5 would be overkill and not worth the extra money (on my speakers). I should make the point again that those with slightly less efficient speakers would benefit from the XA60.5s.

Kent recommended the XA100.5s over the XA30.5, noting that in addition to power and current delivery, there are other improvements that put these monoblocks in another league sonically and when played at precisely the same volume (important point). At the same volume, sound output, I noticed specific differences between the XA30.5 and XA100.5 which I mentioned in my previous post. He did not elaborate much beyond that, but suffice to say he felt that for the Sophia II's the XA30.5 is a perfect match, the XA60.5s would be a sideways step, and the XA100.5s are the sweetspot in the XA.5 line (he prefered these to the XA160.5 and the XA200.5), so if I had the urge for Pass Lab's best, go for the XA100.5s, but the XA30.5 makes the most sense.

Having said that, I have not compared the XA30.5 to the XA60.5s and I have been told by Mark at Reno HiFi that he does not share Kent's assertion of the XA30.5 compared to the XA60.5s, even on Wilson Sophias. He feels that there is a significant enough sonic improvement between the two that justifies the price, even with efficient speakers. Also, I think I read someplace on the boards that one XA30.5 user found the amp to be inadequate with his Wilson Sophias, so as usual it depends on your situation, system and listening environment.

By any chance has anybody compared the XA100.5 to others in the XA.5 family, specifically for cases that don't have possible power shortage? There is just no way that Pass Labs intentionally designs their mid-level amplifier to be better than the upper 160.5 & 200.5. In fact before the XA.5 line exists, Pass Labs told me all XA's are made the same way, except for power difference. I can see the 100.5 be better than the 60.5 because there can be more to power than the ability to play it loud. But the other way around is a bit hard to believe.

I have only heard the XA100.5 in the XA.5 line. I have read people refering to a "sweet spot" in the various Pass lines. The Aleph 2 in the Aleph line, the XA 160 in the XA line, the X350.5 in the X.5 line, etc. I read somewhere Nelson Pass or one of the employees talking about this. I think they are refering to the price/performance ratio which can be a moving target depending on which generation of amps you're talking about. I don't think it is just more power or stereo vs. mono blocks.