Today, when I turned on my x1850 a crackling noisy sound appeared from all four channels. It turns out that this sound is only present when the input selectors are set to analouge input channels, phono and line. The crackling sound is present without music being played and is also lighting up the first led meter on all four channels. The sound stops when the input selectors are switched to the three digital input channels Digital, USB and dvs. I’ve turned the power on/off including leaving the mixer without the power cable connected for a few minutes. Anyone knows this failure and what needs to be fixed?