[rdale]

One guy who I would describe as a genuine 'Audiophile Genius' is Nelson Pass. See: https://passlabs.com/

Nelson Pass has designed a series of innovative amplifiers that he sells as commercial products. He also releases circuit diagrams and build instructions his amplifiers, and helps out DIYers on public forums.

In contrast, it is great that NwAvGuy has designed a budget headphone amplifier, and released the design with a no derivative works allowed Creative Commons license. But that falls a long way short of what Nelson Pass has produced over the years in my opinion.

I think if you asked Nelson Pass whether or not all 'decently made' amplifiers sound the same, he would suggest you need do a bit of listening to different high quality designs.