Please Read and express your feelings and opinions....

@geoffkait 
There mere fact that these snake oil tweaks get nothing but gloating adoration and no criticism for the results by those who try them strongly suggests that it's a psychological phenomenon, not an objective phenomenon. Since you're so fond of wrongly citing rational arguments as "logical fallacy", I'll point out your very real logical fallacy. 

geoffkait - ....No controversial audiophile tweak has ever been proven to be a hoax or a fraud. - old audiophile axiom.

@geoffkait
Nor has the impossible ever been proven to be the possible. An old opportunistic axiom. 🤑

@kosst_amojan

Excellent points... I am learning amp design very slowly.  
My old buddy is designing a couple of Pure Class A amps now,  and he is no different.... He actually forms complete circuit layout in his head before he lays it down on paper... Then he builds, then he listens, then he changes, then he listens. When he gets it right, he'll etch his own boards. These days he is convinced that micro circuitry will sound best. 
Unfortunate for me,  this is over my head.  I can follow a schematic, but I don't have the knowledge to lay one out. The most that I can do is to make a few parts changes when finished understanding that one cap or resistor sounds differently than another.  

My opinion on the "failings" of yester-decade's gear is if those characteristics were desirable, why isn't anybody listening to wax cylinders on hand cranked phonographs? After all, the motorized, tube amplified, voice coil driven sound of the 30's was an evolution of that.

While that is true, its a simple fact that no-one is listening to 30's technology around here. The list of improvements is much to long to list here- and I'm sure you are aware of them.

...The hardest thing I've had to do is learn to listen for what distortion is. That has brought me into strong agreement with the belief that dynamics are closely associated with distortion.

+1

IMO/IME, about 95% of the time when audiophiles use the word 'dynamics' they are really talking about distortion and that word can be safely substituted into the conversation without changing its meaning.

The reason this is so is because the ear uses the higher ordered harmonics to sense sound pressure (GE demonstrated this in the 1960s but little was done with that research). This is probably due to the fact that pure sine wave tones don't exist in nature.

Its right at this point that our philosophies about how to get good sound probably differ; I am of the opinion that since our ears are so sensitive to these harmonics that its not a good idea to do anything design-wise to generate them and so specifically avoid doing that in our designs. This means that I don't use feedback because feedback, while suppressing distortion, also adds some of its own, and all of higher ordered harmonics which can be easily heard.  So if I can do a design that does not make those harmonics, it will be smoother and not sound 'loud'.

I've been accused of using 'antiquated' technology in this regard and that is true, but SITs were a short-lived technology in the 1970s and there were no small signal and driver devices that were SITs- only outputs. Regular transistors just don't have the linearity **and** soft clipping to do the job. That is why tubes are still around BTW; if really inferior (and not just antiquated) they would have been gone long ago.

@atmasphere 
"Each 2150 uses global feedback (proudly: its manufacturer suggests that manufacturers who don't use feedback simply don't know how to do so properly)" About the Boulder 2150 from Stereophile. Different strokes for different folks. 

I've heard noise about SITs coming back a bit on account of them being more efficient at converting and inverting AC and DC back and forth. Who knows.