SET 45 Amp Driving Dynamic Speakers

I think that most often people who are SET fans arrive at that point after going through a range of other choices.  Low-powered SETs tend to be an end-point only after a long search because it takes some experience finding the relatively few speakers that are compatible with such amps (many high-efficiency speakers are highly "colored" as far as their tonal balance so you have to find the few that are not so odd or learn which "color" works for you).  It can also mean giving up a little on some of the more obvious attributes (like extremely deep bass response and bass punch) for the more sublime attributes of SET amps and compatible speakers that one learns to appreciate after long-term experience.  So, in that sense, I agree with Charles.

But, in this day and age, where "knowledge" so freely flows on the internet, I can see Mapman's point that a lot of inexperienced listeners could be seduced into trying SET amps at the outset (it took me YEARS before I even learned of their existence, today just google "best amp" and you are there).  I fear that it is the case that many are tempted to try SET amps with incompatible speakers and/or assume that cheaper SET amps will do the trick because they should not cost that much to manufacture (because they a simple and have few parts).  The problem with that is that those parts can be very expensive to get right, particularly the large, air-gapped output transformers that can handle the high standing current in the primary without over saturating.   You will find a lot of internet posts from those saying that the SET amps they heard are crap; I bet that a lot of this comes from listening to such "bad" setups (easier to be WAY wrong with SETs that with any other kind of amps).

While I agree that it is far easier to get quite decent sound at a reasonable price from Class-D amps, I have not heard any "all out" assaults on top quality sound that involved such amps.  I admit that I haven't heard too many in high-end systems utilizing Class-D amps, but, those that I have heard were somewhat disappointing (e.g., Devailet and Rowland) because they just sounded a bit dull and un-engaging.   In a lower-end system, I thought that a Bel Canto amp sounded pretty good for the money.

Hi Larry,
There could be a few newbies to High End audio who begin with SETs  (admittedly I have not done a survey) . As you correctly acknowledge it more often tends to be very experienced listeners where SET is an endpoint destination . Again you correctly note the barrier to sucessful adaptation,  simple circuit but high quality parts/implementation are mandatory. The lower quality niche of SET will more likely fail to impress with their poor transformers and power supplies. Finally proper speaker match takes some knowledge and time. It's worth the effort in my opinion. 

Larry I respect Mapman's insights and experiences.  He has found much satisfaction with his class D amplifiers and I sincerely congratulate him.  My exposure and listening to class D experiences are parallel to yours , there's just something missing that leaves me unfulfilled.  As we both recognize these are simply individual impressions,  no doubt that there are many happy users of these efficient amplifiers. I don't question Mapman's  contentment by any means. I know what musically touches me but appreciate we all choose our individual paths. 
Charles, 

Larryi the Class D amps I own and have settled with currently are Bel Canto ref1000m in my main system and C5i integrated in my smaller setup.   Both are simply wonderful devices.  

Id like to add a third system built around either SET or OTL amps but space is limited.  

My experience is similar to Charles. I have Zu Definition 4s (reported to be 101db sensitive) and an Ancient Audio 300b SET. The Def 4s have their own integrated "subwoofer module."   Recently, the tube amp required servicing; and I used a back-up 80 watt SS amp for a few weeks. It was OK, but lifeless compared to the SET. This was most noticeable when I re-inserted the 300b SET tube amp last Thursday. Curiously, I did not have to adjust my usual pre-amp volume setting to "accommodate" for the higher output of the SS amp. I listen to almost everything: classical - both chamber and full-orchestra and chorus, jazz, classical rock, female vocals, etc. It did not matter; everything sounded better with the low-powered SET.

Inna and Charles,  I've experienced some really engaging conversations with fellow audiophiles, discussing everything from the flow of electrons to the flow of notes.  The fun part comes when I tell them I don't own a table.   Suddenly, they look at me as if I have giant lobsters crawling out of my ears.  I do love vinyl, but I don't really like the work and frustration.  I love what vinyl can do so well, but I also like what really good digital can do well.   I have an extensive digital library and really have no desire to go back to vinyl.  That is no more likely than going back to SS amplification having enjoyed a really good 300B SET design.  I think Charles and I are in a good place.  Call us crazy if you want.