SET 45 Amp Driving Dynamic Speakers

I've often been amused by the comments in Stereophile about how an SET can measure so poorly and yet sound so good- and further that no-one seems to know why. I have to assume that they did not ask any designers when that comment was made.

IMO low distortion is pretty important, and as long as you don't push them hard SETs can have distortion lower than any solid state amp. And when you ask a little more power, you get the 2nd harmonic which is a lot less offensive to the ear (even in large quantities) than the higher ordered harmonics of solid state! So its no surprise why SETs have a following.

I’ve only heard SETs with horns at an audio show. I recall an Art Audio amp with PX25s driving Avantgarde speakers (Duos?) that sounded REALLY good. I don’t doubt that 45s et al can sound even better with horns.

What I am saying is that those who don’t want horns (for space, budget, WAF, or other reasons) can still get a lot of the virtues of SETs with well matched, higher efficiency, dynamics. That was not at all the impression I got before trying it for myself. I know there are always trade offs, but, in my case, I have a hard time perceiving any significant ones.

Horns are not an option for me, at least right now. Maybe there’s an amp out there that can give me the the "magic" of my 45s AND greater dynamic headroom, with my current speakers. I’m not chasing after it, though.

"Technical facts" by no means tell the entire story.  As has been mentioned on this site numerous times,  measurements and specifications play a fundamental role primarily in determining electrical matching/suitability of audio components.  So it is an effective screening tool. I'm unaware of anyone here disputing this point. What determines if someone will be happy with chosen components is listening to them following the initial screening. It's a two stage process. For my purposes listening is required to make judgements regarding the merits of audio products. Others may utilize alternative methods. 
Charles, 

Tommy,

I’ve heard all forms of demos at shows also, including very expensive high quality SETs using similar very large efficiency horns (with correspondingly stunning results).

The best thought out and executed ones, SET or otherwise, always exceed those that are compromised in some way.

Because of the few watts used, the difference between the best (large GOTO custom horns and bass bins comes to mind) and worst (Zu Essence is one that comes to mind, fine for acoustic jazz, very meh for rock/pop) SET demos I hear are perhaps among the most extreme possible.

So the ante is upped whenever one device asks more of another. That can be a SET asking more of the speakers (be more efficient and an easier load) or the speakers asking more of the amp (give me lots of clean undistorted power please).

Lots of ways to skin the cat acceptably perhaps but only only a few ways to really do it right/best.

I feel I’ve done it pretty well the second way currently at home (compared to the stellar SET demo for example I have heard as a reference among others) and look forward to giving the other way a try someday starting with a separate system on a smaller scale that I can compare and contrast with my in home larger "reference" system.

In the end its all a matter of expectations and how well things are executed together to meet them.