C'est un problème que j'ai eu à quelques reprises , notamment quand j'ai testé le 3d lab nano ou le belcanto refstream , en lieu et place de mon nd5xs en tant que drive du hugo. le hugo est alimenté par batterie , et sa prise secteur n'a que deux broches, (comme le bluesound node),
comme toute source Naim , le nd5xs est mis à la terre,
sur le fil cité par Rico, il y a cet extrait du FAQ Chord Hugo , Cette astuce permet de mettre à la
Naim amplification has the mains safety ground and the signal ground separated. Naim grounds at source.
To ensure that there is no possibility of mains hum or buzz when the Hugo is connected to a mains charger, it is simply necessary to ground the Hugo as it will be a source component, and Naim expects it to be grounded.
The easiest way is to connect a wire from the earth pin of a standard 13A plugtop to the Naim Supernait terminal marked 'SIGNAL GROUND' on the back panel. This terminal is internally connected to the braid of the signal connections connecting Hugo to the Naim amplifier.
There are no high currents or voltages involved and a simple piece of thin flexible insulated wire will suffice.
The 13A plugtop with the single earth wire added is plugged into the wall adjacent to the Naim amplifier mains plug and completes the ground path and eliminates the hum.
(This is often not required as introducing a correctly wired Naim source into the system will deal with the signal and electrical ground connection and so no hum would ever be experienced.)
En gros dans le cas d'une prise uk, il suffit de connecter la broche de terre via un câble isolé au plot signal ground , normalement dédié aux LP. La broche de terre c'est la grosse broche
Install: S1, S2, S3
ma platine fonctionne sans problème et sans buzzz 
