I have it on good authority that a MUON Pro, when added to the Bacch4Mac Mini, makes a huge sonic improvement. I borrowed my Bacch4Mac setup to a friend. He discovered this. I have a MUON Pro on my BACCH-SP adio and my Grimm MU2. I was impressed after adding one to each. Just sayin....A little bit of an update for those who may be interested. I'm running BACCH4Mac intro on a M4 Mac mini, feeding out on a Sablon Evo USB cable into my Lampizator Atlantic 3 DAC.
I wanted to experiment a bit. The BACCH output from the mini sounded surprisingly close to my Grimm MU1 -> Lampizator via Shunyata AES/EBU cable (I believe it's a Sigma, though it could be Omega.)
I ended up ordering a JCAT XE USB Evo card from Kitsunehifi.com that I installed in a Sonnet SE1 thunderbolt expansion case, and plugged that into the Mac. I also ordered a couple Plixir power supplies, but they haven't arrived yet. The JCAT is streaming and burning in. It fundamentally works.
I haven't listened carefully, but very casual listening this morning while I was getting ready was more than a bit encouraging. The system sounded both smooth and detailed. The word in my mind was "fluid," despite running off cheap switching power supplies. (I wouldn't have described it as "fluid" before this change.)
So for anyone curious: yes, you can set up a Mac to use an audio-oriented external USB card. Whether or not the results are fantastic / okay / pathetic is still up in the air, though "pathetic" seems unlikely.
Also, consider a Stealth USB-T Select V3 or USB Double Tune USB cable. Shunyata is no slouch, but Stealth is better to my ears. Enjoy!