So looks like external power is mandatory. The unit will NOT power on with just the USB data cable. It comes with a USB to 5 volt barrel cable that you need to use to power it in addition to USB cable. When I use that with my laptop port, I get this:
View attachment 11032
We get that tiny bit of noise below 1 Khz which from testing other DACs I know to be coming from my laptop. They are well attenuated at some -132 dB so not an audible concern but it is worse than powering with Lab Supply.
I then tested it with my Anker portable battery bank I use to charge my phone and I get this:
View attachment 11034
The Power bank is definitely cleaner than power from my laptop. The Lab supply is a hair better but that is it.
Again, these are at extremely low level so I would not rush out and get fancy power supply for it based on this data.
Too lazy to post but I also tested it with a random external USB power supply I had and the noise was half-way between my laptop and the power bank.