Do I need an expensive digital cable?

With chip DACs your working within the limitations of the chip. There’s a reason why ESS based Bluesound is limited to DSD256. 

I am not a fan of ESS based DACs in general. The sound of these DACs in my experience is direct and leans clinical and analytical. There are exceptions and the final result depends on implementation and analog stage.
Soulnote DAC is ESS based. I heard it at a show and it was very good sounding. Yes super detailed and open sound but managed to not veer into the matter of fact, analytical presentation too much. At the end of the day ESS based Soulnote and Bluesound are completely different animals. Simaudio Moon is ESS based as well if I’m not mistaken. Matter of preference. I wouldn’t trade my Meitner for an ESS DAC. 

I’m a network engineer retired after 20 years. Most of those years reading packet traces on token ring, Ethernet and others.  When using a cable to broadcast digital data packets, there’s no sound to it.  Error correction is built in to the transport. Both coax and fiber optic cables don’t improve sound by the useless expense of “high quality” choices.  It’s damn silly to believe that it does. Packets of data don’t sound.  Buy a $5 cable from radio shack, spend $500 on solid silver wire. .  I won’t make one bit of difference.  Those Who argue that are ignorant about how the data transport mechanism actually work. 

Makes perfect sense to connect your radio shack streamer with a $5 radio shack Ethernet cable. The synergy there is undeniable. 

@audphile1 

The Moon 280D does have an ESS DAC, but I don't think of it as lean. I find it a bit on the tubey side. Although I did hear it streaming a bit lean on some Debussy piano music I listened to,

I think what makes the Moon 280D "punch above its weight" is that although it uses an early ESS chip, the analogue software is the same as high-end Moon streamers. Anyway, I'm quite satisfied with it, and I won't be buying anything better unless I get another large inheritance, like the one that enabled me to purchase the Sonus Faber speakers and Moon 280D, which was kind of an add on because I was only supposed to be buying speakers. 

I am listening to an old recording of Frinec Fricsay and the pianist Geza Anda play Brahms' Second Piano Concerto. It sounds great through the ESS DAC. Again, I think it's what happens after the DAC that makes the Moon 280D sound good. And whatever I own sounds better than anything else. Remember the song "Love the one you're with."

@erniesch 

Having studied about networks when I worked in the computer industry, I argued exactly what you're arguing about network packets being checked, so all network packets are the same no matter what cable you use. I also made the argument that my DAC was asynchronous and reclocked the signal. I argued that as long as I could hear the music, a 50 ohm interconnect would work as well as a 75 ohm digital cable. If the packets were getting through then they were being error correcxted.

To test my theory I bought a $14 digital cable and a $249 digital cable. The $249 digital cable won, at least by my ears. The interconnect caused bad jitter. The $14 cable was much closer to the $249 cable, but the $249 cable was the best.

Why? It has much better shielding and its wiring is more complex? I don't know. But I do know that my bias was for all the cables to sound the same. That would have been my bet based on the networking theory that I knew. Anyway, the $14 cable is available to anyone who wants it.