From Pass X250,5 to 350,5 : what to expect?

Fatcataudio, do you expect much of a difference between x350.5 vs x600.5 vs xa160 for either a Wilson Watt Puppy 8 or a Sonus Faber Elipsa or the like? Pass Labs thinks the xa160 should have enough power to handle those speakers. I have my doubt. Yet that pure class A of the xa series is tempting at the 80 db sound level.

I just have to ask if the 350W X350.5 is needed (vs X250.5) for Wilson, why do you think the 100W XA100.5 is enough? Secondly don't the XA and X.5 series (and not just XA.5) double their power going from an 8-ohm to a 4-ohm? Thirdly I heard the rumor that XA.5 is just a quick re-design of the XA. In other word, any changes would be minor given the cost factor. Is that true? Fourthly, we are talking about 75 db for rock music and 55-85 db for classical music. Are you sure that 100W is enough. Thank you.

Tboooe, since I am replacing both amplifier and speakers, info on my existing equipment won't do any good. I am going to go with Wilson Watt Puppy 8, thus rated sensitivity is 92 db, and impedance is 4 ohms. Distance between the tweeters and my ears would be 7 feet. Rock music is typically played at 70 db. Classical music goes anywhere from 55 to 85 db, but then it does not have as high a demand on the power hungry woofer.

Thank you for the calculation, but it's pretty obvious that theory does not match reality.

As to the whole thread it does not seem that there is agreement either. The punch line actually reads 350W is preferred over 250W, yet 200W is as good as it's going to get (assuming the doubling of power for a 4-ohm). To be exact, even 120W is plenty. This does not, I think, help the originator of this thread or myself. The whole discussion is strictly about Pass Labs. So to make sense out of the power vs performance question, design differences between these amplifiers of the same designer must be pretty drastic. It's too bad that Pass Lab does not have enough dealers for a convenient audition. By default, I begin to lean more and more toward Ayre MXR by the week.