Pass XA 160 review:life span is 6 years?

IMHO, once you go Class A there is no going back. That's probably why I prefer the sound of the older Krell/Threshold/Levinson/Pass amps. I thought the Aleph models sounded better than the X-series. I'll have to give the XA's a listen.

"I thought the Aleph models sounded better than the X-series. I'll have to give the XA's a listen"

XA is one notch above Aleph, it keeps all the good stuffs in Aleph but with better bass, image and treble. The difference is not trivia so that no A/B comparison is needed to appreciate the improvement.

"The XA series does run a higher Class A bias though, correct?"

No ! The total bias current is even higher but rail voltage is much lower.

The Pass Labs site has just posted an excellent comparison of XA160 vs X600 authored by Dr. Poltun, director of the archives at the Vienna State Opera. You will find it as a downloadable PDF file at the following URL:
http://passlabs.com/amplifiers/xa160_reviews.htm

Yeah - just so we're clear the issue is that for D dollars you can have W watts from XA series or 5 times that in X series (I'd have to open excel do find the actual numbers, and its probably not linear across the lineup. But that is the idea.). And the XA series dies out at 200W/8ohms while X series goes to 1000W/8ohms. So, another way of putting it, do you want the amp to sound somewhat better, or do you need super super megawatts? The XA series are considered some of the best amps that exist at all at any price.