The real truth... Dacs as long as they are good, don't make much of any difference at all. The biggest thing is to make sure it has onboard lossless EQ, that will make a huge difference
Amps, do make a difference but the differences are definitely subtle.
I have a ferrum oor with hypsos and I also have the topping a90.. I've AB'd them blind with help of my girlfriend..
The ferrum adds some grip and tightness to the bass, and adds some separation and everything sounds more 3d and in it's proper place within the mix. It's also a bit clearer, the A90 there's a bit of a warm veil there, though it's subtle.
The A90 is looser, and more 1 dimensional, meaning the sounds don't take their place as much, more like the sounds are stacked on top of each other, but there's a catch, the A90 brings everything to the forefront, which creates an incredibly intimate and arresting effect where the music sounds more like it's coming from within you than you are listening to it all around you, which for certain music, like folk and acoustic is a very emotional experience, which is why I keep it. Despite having an amp that costs 5× as much money
After 1000$ it's just personal preferance