A question we are asked on a regular basis is how does one cure whine on USB audio interfaces.
These are normally created by ground loops on the system, which are not easy to isolate. There are some suggestions that it is possible to carefully remove the shield from around the USB cable with a knife, however this is not really advisable and on the whole may not work. At best you cure it, at worst you end up with a useless USB cable and possibly damage either your interface and computer.
I tested a device found on the internet from a company in Denmark, with the snappy product name “USB 2.0 Isolated - Galvanically isolated USB 2.0 Full Speed Adaptor” which is simply a plug and play device. It cost 35.00 Euro and does what it says on the tin. I’m sure the guy will ship around the world.