Best Digital Interface

Apples to oranges apt description. Many if not most dac manufacturers optimize usb input, starting to see I2S implemented more often. I2S theoretically better, implementation is the key. I've found maximizing streaming experience is extremely complex. My streaming equipment chain is almost certainly one of one in the entire world. Perhaps the future may bring more certainty to best interface.

During the 90ties and 00decade, i enjoyed a wadia x32 by spdif with a micromega Duo CD 3.1. Since 2013 my preferred dac is a Mytek DSD 192, using the FW-Output/Oyaide-cable! First, i used a windows-PC/Windows 7 Pro with a FW-PCI-Card.
Since 2020, i've got a streamer by apolitan.de and a PCIe-Card/Chipset by NEC (TI no longer avaiable), on going using the mytek. Comparing to a PS Audio DSD, i'm very satisfied by the mytek/no upsampling.
Frontend by ATMASPHERE and high efficiency speakers (4way-full horn), you can hear every breathing! Are there any other members with similar experiences?

@hgeifman --

The answer is very simple.  You have to listen to your system, using various cable connections and decide what sounds best to you.   There is no correct answer for everyone.  

+1

I decided on a music streamer with BOTH USB and AES/EBU digital outputs to my DAC.  I listened AND listened to both USB and AES/EBU connections for several weeks.

After weeks of switching back and forth, I prefer the AEB/EBU connection from my Aurender music server to my DAC.   To my ears, the music sounds slightly better using the AES/EBU Connection.  

For over 13 years my source has been PC-based/HDD; I've used a DIY audio server with AES/EBU output via an RME soundcard, then a USB to S/PDIF converter, then a streamer solution by SOtm, then re-visiting the USB to SPDIF converter (Audiophilleo + PurePower), and now back again essentially to where I started - an AES/EBU output, this time via a Marian Seraph D4 pro soundcard connected to the XLR input of my DAC/preamp with a braided Mundorf Silver/gold digital cable. Even with the DAC clock-slaved by the Marian card it's my preferable sonic scenario.

With this AES/EBU connection the music is presented less congealed, more effortless/unforced, and just slightly fuller and better balanced throughout. 

@phusis - you should try a Pink Faun AES/EBU card (as long as you're not running Linux on Intel cpu).  You can even get it with upgraded OCXO clocks.

I know the Marian Seraph is likely a very good card, but it's geared towards pro audio where you need a ton of digital outputs, lol.

As USB and Ethernet are packet based, you need to clock the timing of packets as well as the digital to analogue conversion. Reclockers only address the USB/Ethernet packet part of clocking accuracy.
The actual digital to analogue conversion clocking has major impact on spacial transparency and attack/reverb of the resulting analogue signal. While this has significantly improved in the last 5-10 years, the remaining room for improvement, particularly on Upsampling Delta-Sigma converters cannot be underestimated. This is why USB reclockers will always be only a partial solution. For this part, low phase noise, high accuracy clocks, whether atomic or OCXO have audible benefits. Since most Dacs don‘t have BNC Clock inputs, this may require both additional word- and masterclocks.

In an ideal world, having the master clock at the DAC, i.e. just before the conversion to analogue would be best, since buffering, error correction and noise suppression could all happen there. Unfortunately USB and Ethernet are both somewhat compromised because they both transport power and data alongside each other with resulting need for galvanic isolation and noise suppression.

In sum, there are good and bad implementations and compatibilities of interfaces and clocking. It follows that there is currently no ‘best’ way of connecting dacs and servers. This is also why the likes of Lumin and Naim are offering integrated DAC/streamer/Server solutions.