When designing a new piece of equipment the hope and desire of the designer is to make something magical. To sound extraordinary.
What in a circuit controls the level of extraordinary and how might one add more of it?
Turns out the trick is not to focus on enhancing sound quality but to design circuitry that does less harm.
That's harder than it might sound because everything in an amplifier circuit has some impact on the signal. Just choosing the best device type opens up a major can of worms. JFETS, vs. BJTs, vs. vacuum tubes.
Each of these design choices takes you down an entirely different path to be worked on.
The designer's ultimate task is to do as little harm to the signal as possible.
That's how we make things "better".