I am new to any audio work. I have an Intel NUC PC with a 3.5mm TRRS out. It doesn't have a have grounded mains plug (I am in the UK). This is connected to a Motu Stage B16 mixer via a TRRS to left/right split XLR cable. I then have a pair of PA speakers connected via XLR to the mixer. The NUC is connected to a separate power strip to the mixer and speakers.
I have getting a very annoying clicking/static buzzing sound. But when I move my connection from the NUC to a proper desktop PC with a sound card it disappears.
Would a USB sound card or DI box (USB or jack one) solve my issue?