Considerations; Ground Loops; Audio Connections; Background Noise - Ecler QEM16-2 Notice D'emploi

5. CONSIDERATIONS

5.1. Ground Loops

We must try for the different mechanical and electrical grounds, as well as the chassis and
connections grounds arriving to the equalizer, 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.
The LINK switch (16) separates the mechanical ground from the electrical one in the unit, so -
in some cases- this can help you cancel the ground loop.

5.2. Audio connections

Usually, many people do not care about the cables themselves. Many times, because of a
bad connection or bad quality cables, there can be important problems during the music reproduction.

5.3. Background noise

Using active circuitry can mean, depending on the actual configuration, a high noise level.
QEM equalizers have been designed to produce the lowest noise level. Apart from the equalizer's
electronics, noise level will directly depend on the right installation and use of the equalizer.
For instance, if high frequency controls are highly boosted, noise level from the connected
devices at the QEM's inputs, as well as the unit circuitry's noise level, is also boosted or increased.

5.4. Cleaning

The control panel must not be cleaned with any dissolvent, abrasive or petroleum
derivated substance else paint and silk-printing could be damaged.
Whenever cleaning should be necessary use a soft cloth slightly wet with water and
neutral liquid soap. Be careful that no liquid gets into the unit. Never use sharp or erosive objects to
scratch the control panel.
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