The MA3 sounds best through its network connection and its inboard streamer. Don’t get hung up on I2s (since there is no real standard). When I owned the MSB Discrete with dual power supplies and pro-usb but I never “bonded” with it. It was fed via an Innuos Zenith Mk3 I had at the time. The MA3 is a real strong performer. Over time I transitioned to a loaded Totaldac D1-Tube-Mk3 dac with inboard streamer and DSD with live power supply. In my opinion and to my ears in my system, I found it more organic than the MSB and the MA3. BUT, the Meitner’s performance over ethernet exceeded that of the Totaldac fed via ethernet. Once I upgrade to the Grimm Audio MU1 server/streamer which feeds directly via AES/EBU, the Totaldac edged the MA3. I have since upgraded my dac to another brand not being discussed so I will avoid “shilling” for it here.
If I could insert anything into this discussion as a meaningful takeaway, it would be to demo and listen to your digital chain as a whole. Dac A being fed directly by server/streamer B requires you to properly match to their strengths. I2S, USB, etc means nothing unless they are optimized for one another. Properly implemented inboard ethernet feeds into the dac typically removes alot of the data variables. My new dac sounds exceptional when fed via ethernet…they did it right. I still happen to prefer the sound, however, via AES/EBU (which is limited to 24/192) from the Grimm feeding the dac directly but the differences are very small.
Try to avoid getting “sticky” with resolutions, PCM vs DSD, I2s, USB, etc because it all depends on the designer and the implementation. Also, the poster who talked about the MSB solution being all in one box obviously hasn’t owned one. While it performs at a very high level, the loaded out Discrete has a couple of external power supplies which requires two power cables, two umbilicals and the prousb module has the fiber umbilical to the external prousb box into which you plug the USB cable. Oh, if you use RCA interconnects then you have to use some XLR to RCA converters since the Discrete only comes stock with XLR. The rechargable remote was cool though.