Are future improvements in Amp/PreAmps slowing to a crawl?

ok, now I’m curious - where can I read about the advances in understanding human hearing & perception thereof (psych. not physiol.) since the 1960s?

beyond any Google or Gloggle?

if you have a book or review paper post the cite & I will check it out

I have access to Jstor and other scientific and engineering sources

@raindance 

You said "Progress will be when a "full function" preamp has useful tone controls once again..." -Wholeheartedly agreed; let's get some full function back. You may not have to use them most of the time, but they are sure a lifesaver when needed.

I’d say about 90% of the problem audiophiles face is getting all the music that is in the grooves and all the data that is on the disc. It’s really a playback problem. The challenge is to resurrect or archaeologically dig up the information, clean it, deinterleaved it, make it coherent, so it makes sense. You are not protected by the Error Detection/Correction algorithms. Only 10% has to do with equipment and even cables.

Without tweaks, without isolation, without room treatments, there can be no high end. There is no artificial ceiling that cannot be broken through, some silly line that signifies Audio Nirvana. There is no hyperbolic curve of system performance. Hel-loo! Those who believe they only have 2% or 5% left to go before they reach Audio Nirvana are simply mistaken. You don’t know what you don’t know. 😳 Think of Audio Nirvana like climbers climbing Mount Everest. Many climbers get up one morning and declare, "Hey, we made it! What a view!" 🏔 Then they’re informed, "Dude, chill! We’re only at Base Camp." Which by the way is only half way up Everest. 😛

ok, now I’m curious - where can I read about the advances in understanding human hearing & perception thereof (psych. not physiol.) since the 1960s?

You gotta pound the heck out of google. Here's a fun one:

https://pdfs.semanticscholar.org/2f03/7a2adec2af5953b4f84ca6b2e2b3f30a3bf3.pdf

And its the tip of the iceberg. Note how the limbic system is involved...  more:

https://pdfs.semanticscholar.org/2f03/7a2adec2af5953b4f84ca6b2e2b3f30a3bf3.pdf

GE did a study back in the 1960s that showed that the brain uses higher ordered harmonics to gauge sound pressure, but the study does not appear to be online. However this particular fact is easy to prove with very basic test equipment. Oddly though, the implications of just this fact are largely ignored by the audio industry.

Going even further back, we've known since the 1930s that certain harmonics have certain audible effects, for example the 7th can impart a metallic quality (and in small amounts; see the Radiotron Designer's Handbook) but this fact again is largely ignored.