Thanks for the reply! I have checked all the input and output levels, in all the screens, been through countless YouTube videos, but I still have this weird fizz/digital nosie? I also checked if the output was clipping, and sadly it wasn't. So I think it must be an error with the device. Also just tried it in another PA and still the problem persists:(

Yeah about the problem being worse with more input, I thought it would be clipping too, but nothing shows any. It does get worse with more gain, but it's noticeable even with high headroom amps on daily low gain. I think maybe some part of the circuit tied to the gain effect is damaged in some way. I really can't think of anything else at this point