Using Mac Mini as streamer plus music server

[David A]

…The reason I want to use USB only because from my google research it appeared USB has best sounding, I think the best quality MQA also only available on USB connection when using TIDAL?…

I've seen comments in favour of USB and comments in favour of ethernet. I don't think it's clear cut and I think it  may depend in part on what source you're using but it may also depend in part on personal taste. Before I bought my own Devialet I had a friend who used USB for years and then tried ethernet, thought it was better, and swapped to it. Since getting my 130 (now a 140) I've tried both, both before and after it got the CI board upgrade and following some of the firmware updates after the CI upgrade. Each time I end up preferring ethernet, even though Antipodes recommend USB. I think you need to try both and see which you prefer rather than relying on Google research which provides lots of reports, most from people who aren't using a Devialet, many/most who won't be using the same source as you are, and very very few who are using the same source as you and a Devialet.

MQA relies on 2 "unfolds" to use their term. The first can be done by some software and by MQA capable DACs while the second seems to be only possible with MQA capable DACs. Devialet's can't do either but Roon can do the first unfold in software. I've tried comparing the Tidal non-MQA version with their MQA version without having Roon do the first unfold and also having Roon do the first unfold quite a few times. Each time I try the comparisons I end up preferring the non-MQA version. I have heard Tidal MQA with a DAC doing both unfolds but only on a very different system to mine (MQA DAC with a different amp and speakers) but I haven't heard a comparison between MQA and the non-MQA version on that system. From the many comments on MQA I've read over the past year or so it seems that some people prefer it, some don't, and personal taste seems to be involved in at least some of the differing assessments.

I don't know whether USB can deliver better results with MQA than ethernet but if you're using a Devialet I think basing your assessment of USB vs ethernet on the belief that USB will be superior without making your own comparison is a mistake. Since your Devialet can't do either MQA unfold, the quality of the MQA stream is going to depend on the MQA processing done by whatever source you use and you are then going to be limited by whatever options that source provides for connection to your Devialet so your first decision is going to be what source you're going to use and there and the merits of USB or ethernet may not be the most important factor in making that choice. If your choice provides both USB and ethernet output then you should compare both for yourself. If it only provides one of those outputs then you don't have a choice and the best one will always be the one you have, whether that be USB or ethernet.

I don't know if there's anything available which will do both unfolds and provide both USB and ethernet output and the question will be totally irrelevant if you choose a DAC which only provides analog output and doesn't provide digital output. I know you can find options which will do the first unfold and provide both of those outputs because I'm using one and there are others but arguably none of those are going to provide the best quality MQA because they're not doing both unfolds, just the first one, so you're missing out on some of what MQA offers. Whether you use something which does one or both unfolds and provides digital output there's still going to be the question of whether you are one of those people who prefer the MQA version or the non-MQA version of the music you play.

My advice is:

1- first choose a source and deciding whether or not you prefer MQA should be part of that process but that is unlikely to be the only relevant factor you should consider. If you already have a source then your options in regard of USB and ethernet connection are already determined, you either have one or both. If you only have one connection option, whether or not it's better than the other in theory is irrelevant because the option you have is always better than the option you don't have, irrespective of what theory says.

2- if the source you have or choose offers both USB and ethernet connection options then try both and see which one you prefer rather than relying on Google or any other source of opinions. One may have a theoretical advantage over the other but there's also the question of the respective quality of the 2 outputs on your source device, the respective quality of the USB and ethernet inputs on the Devialet, and there's then the issue of personal taste. You should not assume that one will always be better than the other regardless of the equipment involved.