Pass XA-160 and Avalon Eidolon

Depending on your room size you may or may not need 160Ws of class A power.

I have Eidolons driven by VAC PHI 70 monos, sometimes with Canary 309 (similar tube config) , and sometimes
counterpoint Natural Progression Mono w AltaVista upgrades.

I also have a good friend with Ascent IIs driven by Pass 350.5. My impression of the Pass .5 is that it's almost as good as it gets with Solid State. Plenty of well controlled bass to feed the hungry Ascent IIs. The Pass also has the added plus of not tiring to the ears.

Now back to Eidolons. I dont think Eidolons need a lot of bass control power / current (which the Spectrals are known for with Ascents and Radians). You need a pair of SMOOTH tube amps (Conrad Johnson too thick, Audio Research not smooth enough) such as VAC. I had the Vintage 100 Monos driving the Eidolons for a while before I bought the PHI 70s as my main reference.

A summary of my opinion: For Eidolons you do not need too much power, you need a good solid 50 Watts of smooth and stable music power, that's it.

-j. wu

I agree with Johnsonwu 100% - need a good solid 30-50 Watts of smooth and stable music power. In fact two best combination I have tried with my Eidolons so far, was 16wpc Ancient Audio SET amp and GM70 based, 35wpc amp DIY amp.

BTW - I have owned Lamm M1.2Reference for almost a year and I was not quite happy with them. They are not warm enough for Eidolons IMO. I'm just trading them for Cary CAD500MB monos, which are far superior with Eidolons (at 1/3 of the price of the Lamms !).

Pass are great amps. Should do what you're looking for.
Another amp to consider is the Levinson No.33H monoblocks. All the qualities you mentioned.

I am not sure how much better / different the 33H monos are compared to the old ML-333.
When I just got the Eidolons about 6-7 years ago I was using the 333 to drive them and I must say it was so disappointing I thought the Eidolons were incompetent.
If the 33H sounds like the old silky ML2, then I would agree that they'd be a match.
If they sound anywhere near the 333 then it would be disastrous.

The guy I bought my Eidolons from was driving them with all Pass and 160's. His room was much larger than mine and the positioning was maybe ten to twelve feet apart very toed in and about three feet from an all glass back wall.
We listened to CD's for about an hour. I new there was more to these speakers than what I was hearing.

Once I got them set up at home, using the Avalon positioning method as a guide and driving them with my Audible M3A and my trusty PS Audio HCA-2 that they truly came alive. Even though this guy's room and setup made it difficult to hear his system properly he played the SFSO Mahler No.6 2nd Movement. The same piece in my room was much more fleshed out. When he increased the volume for only a few seconds they sounded uncomfortably loud. I've had them much louder and they're very easy to listen to, not at all fatiguing. Just how much his setup or the electronics contributed to the poor sound he was getting I won't speculate.

I'm hoping you'll consider auditioning Ayre's new mono blocks and report back.

Sorry I'm not much help but I'll vote no on the 160's.