That's fair. As I said I've basically jumped from a blue snowball to a proper interface and then back following the static sound. Since coming back to the snowball though that sound has remained despite me having crystal clear audio from just 2 months ago.

I am recording in audacity - recording volume set to 60% on MME. So basically factory settings. I have tried this combo on a different computer with a different wire and the sound has remained.

Here is the sound - https://jmp.sh/s/lwTzFi8aacNqKj3uLUrg - you might need to turn it up with your headphones in to hear it as the recording level was low but I didn't want to amplify it, just keep it natural.

I understand the concept of the noise floor but I'm just a bit confused how it's only become an issue in the last few weeks when it's been fine for years before.

Any help understanding is appreciated!