More power or better quality power?

Ohh yes I guess those tube guys don't care about neutrality anyway as they continue to roll their tubes...

I do believe that if one amp/preamp sounds substantially different when level matched operating within their linear region, then one of them is broken (possibly by design).

In my opinion, I don't believe one design is broken if it does not sound the same as with another design. Speaking out of common sense, all designs, be it amps or speakers are all different. The parts inside the amps, the type of parts, the arrangement of electronic boards etc. are all different and that explains to why they sound different. In general/theory, an amp is supposed to be neutral, in fact everything should be designed close to as neutral possible so as to reproduce the signals in their true state. This doesn't appear to be true in actual case. Designer's may be striving to achieve neutrality but most equipment more or less have their own kind of sound due to the points as mentioned above. The term is subjective and debatable. In fact, I don't know how we can classify any particular equipment as neutral. Only if we can measure neutrality.

More technical persons would be able to explain or clarify in better terms.

In response to the poster of this thread, it would be good to get a quality integrated amp as opposed to using your NAD as a line stage in the long run.

Bob,

We agree that speakers are the "most important" component (have the most influence on sound) but that is about all we agree on, I think. I'm really not sure how you could *not* hear major differences, irrespective of power, between, say, a class AB SS amp, an OTL push-pull tube amp, a digital amp, and a single-ended tube amp, so I don't know. They all tend to have rather distinctive sounds, though ranking one or the other as best or better is largely taste.

Here's a little story (which I am making up right now). A subjectivist and an objectivist were going to go out for dinner. The subjectivist says "Let's go to Vito's, this killer Italian place I know - you'll be amazed." The objectivist replies, "Ha! I've measured the food at McD's and found it to have comparable or better calorie, protein, carbohydrate, and nutrient specs than Vito's. You're kidding yourself to say their food is 'better'! It's placebo effect!"
No offense. :-} I hope that was at least passably amusing.

P.S. Objectivists take all the fun out of audio.

I think others would agree that you start with a pair of speakers and build a system that maximizes their potential. The speakers are like furniture in your room. They are selected by their size, looks and sound qualities. Their placement and interation with the room remain constant. You are using them off in a corner. Different speakers may or may not be an option. If they suit your situation then I would keep them. They have a lot of good press, and I don't think they are your weakest link. The NAD is upper mid-fi. Recommendations from other Sonus Faber users would be the direction I would take.