SET 45 Amp Driving Dynamic Speakers

Hello Inna, IMO nearly  the entire endeavor of assembling an audio system is subjective.  You listen to components and it is either yay or nay.  You either like the resulting sound quality or you don't. Listening to music is an emotional experience.  How does one eliminate the obvious and innate subjectivity aspect? Who decides their satisfaction with components/system without use of their ears?
Charles, 

Charles, of course it's an emotional experience and I would be the first one to defend the subjectivity, I just invited everyone not to get cocooned in it while communicating and conveying certain aspects of the subjectivity. Even each instrument has its own 'subjectivity', in a manner of speaking, its own unique voice. However, low powered system, or an instrument, would have too many limitations, and no matter how great it may at times sound, this would not be enough for me. Speaking of instruments, the greatest I've ever heard was a Conti custom guitar played by Paco de Lucia. Yes, it was made as a flamenco guitar not classical or blues guitar, but I am quite certain it would play anything extremely well. If it was still a compromise - it was a great one. Anyone heard Amati or Stradivarius ?

I have no problem with someone who tries a low power SET amp with well matched dynamic speakers, and concludes it doesn't work for them. What bothers me is that all the talk about these amps REQUIRING 100 db + efficient speakers dissuades people from even trying a setup like mine.

They may find it doesn't meet their needs, but they may also be very pleasantly surprised, like I was.

One of my most memorable experiences was listening at home after attending a live orchestral concert, and thinking "Wow, this actually sounds like what I heard in the hall!".

Massed strings in the concert hall can have this amazing "singing" quality, which is hard to reproduce at home. My system got it right (among many other things).

IMO nearly  the entire endeavor of assembling an audio system is subjective

I started out that way because I basically knew nothing about how this stuff really works.   I even lost interest for years because my sound was not what I wanted and I was too lazy to figure out why. 

Things changed when I started to focus on really understanding what was going on.    I was on teh right path soon after and finally found a happy place after not too long.

There is a difference between what one likes which is subjective and the decision making process that gets one to their goals.   That is best driven by objective learning to meet ones subjective goals.

Everyone ends up differently as a result because we all have different goals but there are right and wrong approaches to most any undertaking.  

2nd order can sound good to the ear. Enjoying our system choice is what its about not if its optimal or not, so if you like it dare I say its right.

The concern of course is not the 2nd harmonic, but the presence of the 5th and above.

100 db peaks is definitely desirable in a good hifi system. In fact it should be a basic criteria while choosing the speaker-amp-room combo. But 100 db continuous SPL is very loud.

This. 100 db peaks should be no problem for any system, that is if you want to be able to reproduce 90 db correctly. Most peaks don't show on a sound pressure meter as high as they really are due to their transient nature.

What bothers me is that all the talk about these amps REQUIRING 100 db + efficient speakers dissuades people from even trying a setup like mine.

I think you might be missing my point. Clearly there is something about that type 45 amp you like. My point is that with more efficient speakers you would like it more, as the more efficient speakers can bring out more of that that amp can do right. I am speaking from direct experience here as I have had type 45 amps at home for years.