pass labs xa30 to valve amplifier.

Pubul57,

"I'm thinking there is something about multi-driver speakers that makes a difference in the simple sensitivity/watts equation we normally make"

I've heard/read that complex x/o's eat up power. That and the fact that you have the spectrum of music coming out of poly?/woofers, kevlar?/mids, titanium?/woofers at the same time makes me wonder how I was able to enjoy music out of "those" types in the past. The answer is, my ears didn't know any better.

These days, besides my Maggie 3.6's, I like a good 2 way with a x/o around 2.5K or higher. Trick is getting a mid/woofer to play nice up to and thru that point. I favor soft dome or ribbon tweeters also. Add to that an impedance (nice if it's 8 ohms) that doesn't vary much (say 20%) and it becomes a recipe for pleasure for me.

Pubul57, as best I can make out, Bobby is pretty conservative with that 89db rating on the Merlins.

Multi-way speakers with complex crossovers DO eat up power. The phase angle and impedance both need to be factored in when choosing an amp....at least on paper.
Big impedance swings with a hi phase angle at some low dip in impedance is a recipe for 'Don't Buy Tubes'.....

That's why, IMO, the 'conventional wisdom' of Maggies being a bad load is a bunch of hooie. They mainly resistive or moderate phase angle nature of most of 'em make it a reasonable load for amps which can be happy with the lowish impedance and sensitivity.

Ralph, I also think the XA30.5 is very conservatively rated, but one might still need the more powerful XA amps, even with "sensitive" speakers if they loaded up with drivers and x-overs. I think, but I'm not sure, that ight be the case with Pettyfeversk's speakers and why moving up the power chain with Pass has proven to be a worthy improvement for him.

Yes, pub, per the Stereophile measurments linked above, it'll go to 130@8 and nearly 200@4.....
However, at that point you're clearly in A/B.