Ecler DAM614 Notice D'utilisation page 7

Ground Loops
Care should be taken, so that the different mechanical and electrical grounds, as well as the
chassis and ground connections arriving to the device, to be independent from each other.
Ground loops can be easily detected through a low frequency hum noise (50Hz). Depending
on the level of this noise, it can interfere on the music quality.
Audio connections
Usually, many people do not care enough about the quality of cables. Many times, because of a
bad connection or bad quality cables, there can be important problems during the music reproduction.
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