Constant buzz

I noticed that whatever I plug into the external audio IN of my AR MK1, (any source, whatever cable I use) I hear a buzz at the main outputs of the unit, even when the sequencer is stopped. This buzz is proportional with the volume output. The level of this buzz is not significant, I mean, when the unit is playing at normal level, the ratio level/noise is very high, and the noise is no longer hearable.

I have three questions:
1 - Do all units have this issue ?

2 - Is this identified as a problem or a behaviour that users have to live with?

3 - If it is a problem with my unit, can it get a chance to have it fixed ?

Thanks for you feedback on this !!
Happy new year 2021, hopefully, I should be better than this damned 2020…

I noticed the same running my Minilogue via the EXT IN - I only notice it when adding gain in logic/ableton to mix my track.

I have isolated my problem to the EXT IN and couldn’t solve the problem despite turning dist/comp off.

Anyone else have similar issues or have an explanation?

Depending on what part of the world you are in this could be a 50 or 60hz mains hum?

Thank you for this info. I am waiting for a response from Elektron, I’ll see what they suggest.
I did no go into all the details of the RANE paper, if you did, is there a workaround for my issue? Special cables ???
Thank thy for your help