Sounds like a grounding problem (hopefully) rather than a caps problem (not so good) since it goes away in balanced mode.
As to what to do about it... check your power cord and the mains plug. Failing that, I think you're better off speaking to a technician.
Of course the french explanation will prime over all of what any of us have to say.
As to what to do about it... check your power cord and the mains plug. Failing that, I think you're better off speaking to a technician.
Of course the french explanation will prime over all of what any of us have to say.