It's interesting that Lumin may be onto something with their X1 DAC/Streamer as it has a native fiber connection in addition to the copper Ethernet (RJ45) connection. I've heard and read from X1 owners that the fiber optic port is noticeably better than the copper Ethernet port.
If you stream music from the internet, I can't recommend this more highly
I had been using a Roon Nucleus to stream Qobuz, with my Chord Qutest directly connected to the Nucleus. I thought I was getting pretty decent sound quality. And then I got a marketing email from Small Green Computer touting some of their optical gear. The basic idea is that normal cables and connections used to stream from the internet pick up noise of one kind or another (radio frequencies and electromagnetic something or other). But fiber optic cables and their connections/interfaces do not. I don’t know anything about anything, but it made theoretical sense to me, it wasn’t a huge amount of money ($1,400), and with a 30 day return policy I figured I could always return it if I didn’t hear any improvement. Well, I didn’t just hear a slight improvement; it was like turning on the lights in a dark room. Much greater clarity and detail, much better micro and macro dynamics, better timbre to acoustic instruments -- overall just more lifelike. Two quick examples: I’ve listened to some of Steely Dan’s top songs 100s of times over the course of my life, and this is the first time I’d ever noticed a particular and very subtle sound characteristic of Fagen’s keyboard in Babylon Sister. It’s hard to describe, but it’s like there’s a slight sound of air being exhaled by it. The other example: the specific timbre of whatever percussive instrument is used at the beginning of Copeland’s "Fanfare for the Common Man" (a recording by the Minnesota Orchestra). There’s more of a metallic sound than a drum skin sound to it that I didn’t know was there before. The metallic sound starts in the center and then projects out and to the sides, like a wave washing over you. Anyway, I’m just thrilled about having stumbled upon the whole "optical" thing and felt obligated to let others know about it. If you stream music over the internet, I highly recommend giving it a try. (The product I got was the opticalRendu, with the linear power supply option, and the Fiber Ethernet Converter Bundle option.)