Line Filters and OP-Z Earth Loop Noise

When I was much younger, and vinyl records were a thing, I used to have a problem with earth loops between the turntable and the amplifier. The problem was that both the turntable and the amplifier were connected to the electrical earth for health reasons (my health not theirs). Then, when you connect a cable to send the signal from the turntable to the amplifier you add a second ground connection which causes induced noise. You had to fiddle around with the earth signals to get rid of it.

Fast forward to today and I’m connecting my OP-Z to my computer using the audio and usb inputs at the same time. Which makes another ground loop and more noise. There is a way that you can try to address this by turning off the USB charging on the OP-Z (Press [Screen] + Keyboard (E) - Spark) but this limits how long you can play with it and doesn’t always work. Instead I’ve got hold of a ground loop isolator which contains a tiny transformer that electrically isolates the input from the output. It reduces the level a bit, but it also makes all the nasty noise go away, which is what I want.