Would You Rather Own A Good SET Amp, Or A Great Push Pull Amp?

Yes- I mentioned some prior, such as understanding the harmonic spectrum created by the amp. IMO that is more important than the THD. 

@atmasphere ,  it would be interesting to detail this point: which are these important parameters that more realistically reflect the real performance of an amplifier, or are they still to be developed? 

I am about to change my earlier  point of view that engineering is a purely applied science. I share the concern by @invalid . I think that before we talk about the amplification, we need to understand how the music performance in question was recorded. That is to say, two things are to be distinguished and seen  separately: Which kind of music we are talking about and how it was recorded (with a single microphone or each instrument separately etc.) , and then how the recorded music is reproduced by some amplifier. I think that the second issue should be discussed based on the analysis of the first one. So suppose for now that we have a "perfect" amplifier of your choice and see how its reproduction is affected by a particular kind of music and by how this music was recorded. 

I suggest that an inherently loud music (e.g., rock) is easier and more natural to reproduce loudly than an inherently non-loud music (e.g., jazz). If we force the amp to play an inherently non-loud music loudly, you may unavoidably get some distortion, regardless of how the amp is built.  By the way, among the two cassettes mentioned in my  previous post, the first one was jazz and the second one was rock music (such an analysis would understandably make less sense for CDs, i.e., it should be an analog source). 

I suggest that an inherently loud music (e.g., rock) is easier and more natural to reproduce loudly than an inherently non-loud music (e.g., jazz).

@niodari All electronics don't care what kind of music you put through them, which is to say there is no way an amplifier can favor a certain genre of music.  The level of difficulty is thus the same for the amp regardless of the music. 

All electronics don't care what kind of music you put through them, which is to say there is no way an amplifier can favor a certain genre of music.  The level of difficulty is thus the same for the amp regardless of the music. 

@atmasphere , I readily trust your knowledge and experience and these observations. In my previous post, I tried to argue that, independent of electronics, on an ideal amplifier, an inherently non-loud music would sound "forced" if reproduced loudly, whereas  an inherently loud music would sound more coherent on that amplifiers on the same volume. I suggest it's more related to the acoustics and how we pensive sound waves. 

Agreed, SET, pp or any amp for that matter should not favor any genre of music over another. With the following caveat; with acoustic music/instruments we have a reference for natural/inherent timbre, a quality amp, regardless of topology should be able to reproduce this accurately. Of course other components of system, room, AC, etc affect this ability to some degree. 

As for loudness of recordings, in general I've found louder recordings to be more dynamically compressed than those recorded less loud. Rock and 'commercial' recordings in general are notorious for this, 'loudness wars'. And macro dynamics are one thing, micro quite a different thing, recordings that are micro dynamically compressed are far more egregious to me, uncompressed micro dynamics bring musicians alive, you can sense and feel small changes in breath, tension on strings. Based on my experience with various amp topologies and speakers, SET and horns are extraordinary in reproducing the finest degree of micro dynamics. My latest push pull doing quite well here as well.

As for sense of SET loudness factor vs PP. I'm presently hearing exactly the same thing I've always heard with SET vs PP amps. This  a more forward sound stage with SET vs PP, with SET certain info, therefore, close miked or instruments/voices recorded with a small boost in db are pushed further out into room, very noticeable my latest PP, front of sound stage only extends to front of speaker cabinet. This can have the effect of making the SET seeming to play louder when in fact it isn't. 

I've also always found preamps to have a great effect on presentation of amps. I have two DHT and one 6sn7 based pre, I can use 71A or UX112A with one pre, the other uses 101D, varying microphonics of these tubes affect overall presentation. 

If there is one thing people should take away from this thread, @atmasphere is entirely on point with the critical need to match amps to speakers, these flea powered SET need something around 100db and pretty benign impedance curves to work within their intended range, IMO. This to be able to listen at volume levels into the 80's which is as high as I go, generally I'm listening in 70's range with my 103db modded Khorns. And I'm not even sure I trust a 2a3 to have the balls to drive these, considering a 50DHT.