Keyboards - Bluetooth

[Atte]

Here we are, again, concerning the MX5500. I'd wondered for some time what's making that creaky sound and as I tried to localize the source, it turned out to be the mouse charging station's power adapter. It was pretty bad, I mean loud. I got the set replaced completely just yesterday, as I was having other minorish issues as well with the desktop. But, the new set is no different. The adapter keeps buzzing/chirping/whirring at high pitch sound level. Only this time it isn't just as loud as the last was.

Is this really an attribute of the set, that you just have to learn to cope with, or should it not be doing that all and be silent?