The iDefender3.0 plugs into your computer USB port and auto-detects if there is more than one earth and will ‘intelligently’ disconnect the computer earth for cleaner sound.
iDefender USB Isolator: https://ifi-audio.com/products/idefender3-0/If your DAC is USB powered, the iDefender3.0 requires an external 5 volts to break the earth. It works pretty well with our 5-volt iPower (just saying!). Injecting clean power will ensure you get the maximum out of your USB audio.
The iDefender significantly lowered the noise floor of the Focusrite 2i2 I now use on the desktop machine for playback.
Without connecting external power the iDefender broke a ground loop that was producing a small amount of hum.
There was still some low-level USB hash.
It comes with a USB C Male to 2.5 mm Female DC power connector pigtail so you can use an off-the-shelf wall-wart switcher.
Once I externally powered the unit from a generic 5V 1A wall-wart the USB hash dropped out and I now hear only extremely low-level DAC noise at death-defying gains.
I'm going to move it to the workbench Focusrite 2i2 and see if I can measure the improvement.
Amazon stock these.
I bought a USB A to A version which looks like it has sold out and has been memory-holed by Amazon.
They still stock the USB A to C and C to C versions.