Gave up my SET----looking for moderate to higher power replacement options

I’ve heard the Benchmark, Mola Mola and Soulution amplifiers (Examples of High NFB circuits) no SET sonic characteristics in my opinion. I don’t deny that many listeners loves these particular amplifiers and in fact I could be in the minority.

@charles1dad There is a reason that I mentioned the bit about the designer paying attention to human hearing rules (I didn't put it in quite those terms). If he's not careful, and does not permit the lower orders to mask the presence of the higher orders, the amp runs the risk of sounding dry. Now if you get the distortion low enough, this phenomena is reduced, but you have to get really low distortion numbers! 0.0001, that sort of thing. So if for whatever reason you can't get there, then you have to be sure that the lower orders mask the higher orders.

To give you more insight on this, almost any solid state amp has less higher ordered harmonic distortion than almost any SET. But the SET has a huge 2nd order by comparison, which tends to mask those pesky higher orders.


(Here's a fun bit: amps that make the 2nd ordered harmonic as their primary distortion component have what is known mathematically as a Quadratic Non-linearity. Amps that have a 3rd as the primary distortion have what is known as a cubic non-linearity. The difference is, if based on the 2nd the distortion harmonics do not fall off as quickly as they do if the 3rd predominates. Since the 3rd is treated the same by the ear as the 2nd (contributes to warmth and 'bloom') an amp that is based on the 3rd will still have a musical presentation, but otherwise will be perceived as being more neutral since there is less coloration overall (the 3rd will be slightly less than it is in an amp based on the 2nd harmonic) due to distortion. This is why I built entirely differential amplifier circuits, as the simple fact that they cancel even-ordered harmonics in each stage throughout the circuit caused it to have its major distortion component as the 3rd. Since distortion is not compounded from stage to stage, the higher orders fall off at a faster rate as the order is increased.)


Obviously the brightness and harshness of traditional solid state that we've heard over the last 50 years (and why tubes are still around) is a coloration too. I don't agree that we hear all that differently: all humans use the higher ordered harmonics to sense sound pressure and all human's ear/brain systems assign the same values of brightness and harshness to these harmonics when they are distortion. IME people express these differences out of expectations of what a stereo should be, if not sounding real. When you ask for the music to sound real, then (again IME) these differences tend to go away and people start hearing the same things.

I have a Sciit Ragnarok which I like a lot. It is probably class AB and I have not compared it to many others. Around $1.7k.

Ralph,
I understand that we humans hear the same in regard to neuro-acoustical physiology pathway or msechanism (Using higher order harmonics to gauge sound pressure and detecting harshness and brightness). I should have been more clear as I’m referring to individual taste/preferences IOW the subjective aspect.

You used the term "dry" and that describes how the 3 amplifiers I cited sound to me (Definitely a subjective judgement). Someone else may describe them as accurate and very neutral. This is the hearing/perceptive differences I was referring to.
Charles

@atmasphere I appreciate your explaination and the educational post Ralph, but I will note that some listeners do find substantial differences between 2nd vs 3rd harmonic dominant designs (e.g., see the "Harmonic Distortion and Sound" section of this article: https://www.passdiy.com/project/articles/audio-distortion-and-feedback).

This even holds when the amplifier typology is otherwise held constant, e.g., when adjusting the front control on the First Watt SIT-1.

Charles---I probably won't (ever) be able to swing the Mola Mola or Soulution amps but am interested in the Benchmark.  I'd be much more likely to seek them out if the used price were lower though.  How did you feel about the Benchmark's sound?  I read a few comments about some incompatibility issues with some speakers?

Mapman---these Focus clones are a fairly good match with 805 based SETs.  The 45w is ample power for the most part.  I just get the itch sometimes to play lounge or dubstep or some brutal bass heavy ambient at un-neighborly levels.  With almost everything else, I never felt I was pushing the JAS hard.  My main listening was jazz and some blues so the volume was usually kept at reasonable levels.  With most other SET amps using other tubes, I would agree with finding the right speakers but I think it less of an issue with 805's.

articdeth---my appreciation of the SET I had was more based on it's pristine sound than tone.  With the right recordings, I was hearing the musicians in the room with me rather than a widow on to  the recording. There was just so much inner detail and (almost) nothing between me and the sound.  Almost every other amp I've used is veiled in comparison.  I'm looking for the transparency and detail I hear about in the best Class D amps without the common shortcomings.   The reviews of some of the First Watt amps sound like what I want, just much more power.

atmasphere---you mention that there are Class D amps you've heard that are very close to the SET sound.  Would you please offer a recommendation or two?  

Many thanks to all.  If I find what I'm looking for, I'll certainly share my experience(s).