I can only speak from using a Mojo or Hugo 2.
If you are using USB from a computer, then the noise tends to be either RFI picked up by the cable acting as an aerial, or electrical noise coming from the computer power supply, or the internal workings of the computer (this includes occasional breaks in the music signal stream, when some of the computer services are given priority over the music stream).
- RFI can be cured by adding a cheap Ferrite choke to the cable
- Changing the computer system priorities can eliminate most of the breaks in signal
- Running laptops off battery removes issues with mains signal noise
The above are things to explore that are cheap, or only cost your time.
Unfortunately the internal workings of some desktop PCs are inherently noisy, and there is little that you can do about it, except try another motherboard, or add an optical output.
I managed to get my computer almost noise free for USB, but Chord dacs do have a very low noise floor, and I could still detect occasional noise - so I tended to use optical most of the time.
Eventually i changed to using a Shanling M1 as my music transport, and this is quieter than the PC or phone. The noise is so rare (ie every few days), that I can never be sure whether it is the Shanling, or a poor rip from a CD. I normally give the Shanling the benefit of the doubt.