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.)
ATMFRANK, do you find a notable additional difference with and without Allo Digione Signature/Raspberry (do you need any special things to install it, it seems it comes without a case right), what DAC you have? 
It’s really hard to say "how much" of a difference something makes, because of subjective listening habits and inability to measure. I dare to state that the Allo DigiOne Signature is an incredible value for the money. It’s a touch better than the non-signature version which I had for the last 2 years. The reasons are mainly these: separate power feeds (clean), galvanic isolation (the previous had that too, but on the same board) and improved clocking.

Allo also makes a USB bridge that conceptually competes with the Rendu and similar products. I didn’t have the privilege to test this out (money is not an object, but time is....)

What do I with the Signature: I am running LMS/Squeezeplayer on it, without oversampling. Because I like to control to oversampling characteristics on the DAC itself, not in software. Although it is nice to have that software option (Foobar) for trial/error and to play around with it. I love the sound coming out the Signature. Someone should put that setup next to a BlueOS or Rendu device and compare, as unbiased as possible.

I am feeding a Burson Conductor 3R (2xESS9038q2m) a SMSL SU-9 (ESS9038pro) and sometimes a Chord Mojo for A/B testing. For the ESS, my personal preferred filter setting is MP/fast (minimal phase, less pre-ringing), which comes close the "Meridian" sound of MQA (don’t get me started....). Playing with OS filter settings and being able to measure the effect on your listening experience is something that takes a long time to develop. It’s fun, doesn’t cost anything more and makes the difference between feeling "fatigue" and "addiction". Again, personal opinion only here.

I use a combination of UniFi switch/cheap Ethernet cable for the Signature setup, and wifi on the other. I sometime switch. Honestly, to my ears, there is zero audible difference between Ethernet and wifi.

Look, I don’t want to put anyone down for feeding the hobby. Many decades I ago spent top $$ for 20bit Audio Alchemy HDHC DAC, which had an "ear-and-mind-opening" experience. Did I regret buying it? No. But I do know that technology get’s better and cheaper all the time. And I just want to make sure I understand the technical reasons before spending more $$$ on the latest gadget. I like to make educated decisions.

Happy listening. -frank
I haven’t followed all of this thread, but is the OP stating that he swapped out ONLY Internet cabling to his device, or added a component to the device(s) too?

I do software for a living, and understand the TCP and IP protocols used to move byte sequences over the Internet. TCP/IP underpins most aspects of Internet traffic: email, web, ftp (showing my age!). When the sender (e.g. Spotify) transfers a ’file’, which is really just a byte sequence, to a receiver (your music box), it adds checksums to ensure any errors in xmission are noticed by the receiver, and fresh copy sent. In essence, TCP ensures that what the receiver gets is what the sender sent.Now, if music streaming is what I think it is, byte sequences of data representing sound files, then there is no way a cable by itself can ’improve’ on the data sent from S to R. Yes, it may be faster, or be higher quality and require fewer re-transmits, but at the end of the day, an Internet cable’s job is to xfer data across its two endpoints, which is likely one small ’hop’ in the larger path from sender to receiver. The cable doesn’t ’know’ the signals its moving are sound files, its just electrical signal representing 0 and 1, each a ’bit’ and we have 8 bits to the byte. Only improved PROCESSING (better DAC etc) of the incoming byte stream can possibly improve sound quality. The D in DAC is a given, it's what TCP/IP does. It's the A in DAC that counts.  And cabling alone is firmly in the D side of things.
That said, I'm off to polish my two grand power cords, they do make a difference, honest ;)
In a home environment, with cheap cables, data losses and retransmits are near zero.  Most people at least admit this. If there is a difference it can only be attributed to EMI/noise.  Ethernet transformers will pass frequencies <1MHz.
Great examples of smart people without experience giving poor advice. "No way"
How about you open your wallet at some point and learn something? Probably won't; too cheap and too proud. :(