I was forced by AT&T in finding the best DAC I ever heard.
I have a Schiit Yggy.
AT&T mandated that I stop using their DSL, and installed Fiber.
The Fiber quieted things down .. apparently the copper running the DSL and the DSL modem attracted noise. AT&T supplied a new hefty looking modem. It sounded quieter and smoother than DSL ever did.
Then one day when checking my modem set up, I realized that by default the wi-fi was always on... and the software for a landline phone was also turned on. I turned off the wi-fi and shut down the phone operation. " New Quiet!" It seems that those two operational features (even when not used) would contribute to activity on my mother board. Noise was being produced.
I connect the fiber modem via an audiophile ethernet cable from the modem to my PC. And use a high quality USB cord to my Yggy. It never sounded as good no matter what modem I had been using.
If AT&T did not force me to switch to fiber? I would still be trying to find some tweak to get things better.... It now sounds so natural. I am a musician. I know what real instruments sound like. I am impressed.