Noise from loudspeaker via Line-in source

[K4680]

Hi, has anyone experienced this problem?
The Devialet is connected via Goldkabel interconnect to a Marantz AV receiver.
As soon as I switch the source to line-in there is a constant noise coming from the loudspeakers (no noise from other sources). The noise disappears as soon as I unplug the interconnect cables from Devialet.
The strange thing is the noise is there even when the Marantz isn’t connected with a power cable at all.

Hello Markush, was that when the cable on the Marantz is disconnected? Cable with Marantz could act as an antenna!
Shielding defective, EM radiation, etc.