SET the best?

I have a reasonably efficient speaker system  (99 db/w) which I run with a variety of low-powered tube amps.  Among such amps is an Audio Note Kageki, which is a 6.5 watt parallel single-ended amp running 2a3 output tubes.  It is a pretty good sounding example of a SET amp, yet, I would not say it is the best amp for my system and taste.  I generally prefer a pushpull 349a amp that I own that outputs 5.5 watts/channel.  Both the Kageki and my 349a amp deliver an expansive and enveloping soundfield, rich pallet of harmonics and a natural presentation without edginess or overly "etched" detail.  They differ a bit in the bass presentation.  The 349a amp is punchier and tighter in the bass, but, that bass presentation is a bit "mechanical" sounding (a sameness regardless of source material) while the Kageki sounds more varied and natural (albeit soft sounding) in the attack of bass notes.  Different strengths and weaknesses, and one is not "better" than the other.

Among the very best amps I've ever heard are a pushpull amp running the 252 tube and a one-of-a-kind output transformerless amp.  Both made my Kageki sound anemic in direct comparison.  While I really like several SET designs, I hardly think that, as a class, they outshine other tube designs.

Not necessarily.  I own two low-powered pushpull amps (both custom builds) and a very good SET amp (Audio Note Kageki), and even limiting the analysis to my personal taste, my particular room and my system, I cannot say that any particular amp is unequivocally the best.  I have a relatively SET friendly speaker system (99 db/w efficient) which is also necessary because my pushpull amps are also very low in output.  My overall favorite amp is the pushpull 349 amp (5.5 watts/channel), but, it doesn't deliver the subtle tonal qualities in deep bass that the Kageki can deliver (it sounds more punchy than the Kageki, but this punch is a bit "mechanical" in its sameness). 

I think that the best amp I've ever heard is an OTL amp that is also a custom build.  It manages to deliver the explosive dynamics and liveliness one expects from an OTL while not being the least bit harsh and edgy.  The next best is a pushpulll 252 amp (a tube similar to the 300b, but not murky and bloated sounding) that I heard side-by-side with the Kageki that made the Kageki sound limp and drab.  The next amp on my personal favorite list would be the Audio Note Gaku-On (parallel SET) or my 349 amp.    

As I’ve said before, all types of tube amps can sound great, or less than great, depending on specific implementation and personal taste.  My favorite amp is a custom-built 35-watt OTL, my second favorite is a pushpull 252 tube amp, and the third favorite is a parallel SET design.  All of these can handle reasonably efficient speakers that are easy loads; there is no reason to exclude multi-way speakers from consideration.  Of my own amps (two pushpull, one SET), my pushpull 349-tube amp is my favorite—it is around a 5.5 watt amp, and it powers a three-way horn-based system.

If you are considering parallel SET, be aware of the issue of one tube in a channel pair becoming much stronger than the other such that, in short order, you lose the full power capability of such amps.  Even when one starts with supposedly matched pairs, they tend to quickly become unmatched.  I've had this happen in my Audio Note Kageki, and others running parallel SETs have noted this issue too.  

I have my doubts about any "cheap" 845 amp.  Many really don't run the specified plate voltage for that tube, and the ones that do, would have to be properly built to be safe to operate, and that means higher cost.   The same would apply to 211 and other higher powered SET tubes.  

I hope the $2,000 budget for a 300B amp is the budget for something used, and is not the budget including the output tubes, because decent 300b tube would eat up a very significant part of that budget.  That would leave not much for other parts, particularly the output transformer which is not cheap in a SET amplifier.  If you can build your own gear, the 300b kit offered by Elekit sounds decent and is quite inexpensive for what one gets.  But, I still have my doubts about "budget" SET vs. the many inexpensive vintage pushpull amps that are available.  There is no inherent superiority of any particular design, and a good pushpull transformer amp and pushpull OTL amp can be the right choice to deliver the goods.

Speaking in very broad, generalized, terms, I tend to find pushpull amps to have a "tighter" more punchy sound than SET amps.  But, too much of that quality and the sound seems a bit artificial or "mechanical" and less natural than the more relaxed sound of good SET amps.  For me, for example, KT88 pushpull amps tend to be particularly likely to sound too punchy and mechanical for my taste, but, as with everything in audio, there are always exceptions. 

I like MANY pushpull amps (this would include OTL amps), while I also like SET amps.  It is never as simple as saying one type is better than another.  Right now, I favor my pushpull 349 tube amp over my SET amp (the SET amp costs considerably more), but, in some respects I still do prefer the SET amp--although the bass is less powerful and tight, it sounds more subtly "musical" (the quality of the bass changes with the music and sounds less "same" and "mechanical" as my pushpull 349 amp).  Both sound harmonically saturated, deliver an expansive and immersive soundstage, and sound relaxed and natural while still being very lively sounding; the pushpull 349 just delivers a little bit more of these qualities.  

Wow! More of the ever-evolving absolute conclusions based on very limited experience.  It is one thing to say that you have heard, and liked, a certain 845 amp running a particular set up, but, that does not then lead to a conclusion that "845 surpasses all PP amplification in all genres" and that PP amps are not needed.  

I have heard a number of 845 amps, and liked quite a few, but, none were clearly better than a whole bunch of SETs running other tubes.  If higher power is needed, does it have to be an 845?  How many 211, 833 and 1610 amps have you similarly auditioned?  In all of these comparisons, how many pushpull amps and tube types have you auditioned other than the Defy7?  Also, OTL amps are pushpull amps--how many of these have you also auditioned?  

I'm with Atmasphere on the choice of tube.  I prefer the lower-powered tubes for SET amps, and I like the tubes in the order he presented--from 300b to 45 (the 45 sounds great if you can get by with a very low amount of power.  My own SET runs parallel 2a3 tubes; I wish it was set up to run 45s instead (some others I know who own the same model of amp run 45s in place of the 2a3, but, the tubes don't last very long).