Marshall speaker emits hissing noise on both line and bluetooth input.

Hey, I have a Marshall Kilburn from 2018 ish that started to emit this horrible hissing noise a few days ago. Everything works as it should (Treble, bass adjust, volume, aux and bt input…) except for this noise that appeared. I've tried the speakers themselves with another amp and they work just fine. Also, when I'm playing music through bluetooth and the speakers disconnected it sounds like music's coming out of the bluetooth module? I'll add an attachment. I'm wondering if i can find some help with this on the forum? What is the hissing noise?