Ok, so just as a bit of an update, as I was getting ready to disassemble it I decided to make a few more tests. I connected it, and suddenly got no noise (after getting noise for hours yesterday). I thought it was because now I'm in my office instead of another random place of the house, but when I touched the cable, the noise came back. Long story short, it seems the connector is faulty. I can twist it a few times and sometimes the noise disappears, not even in the exact same spot, it's just random. I can also make it disappear if I manually connect the connector shielding with the USB shield (just tried putting one of my keys in the connector :D), so yeah, there is maybe a cracked solder joint or something similar inside, I'll have to open and deal with it.
Thanks again to everybody offering suggestions, really appreciate it.
