40
Vincent
Burn in/ Warm up
Your audio components need a certain time
period until they reach maximum performance.
The duration of this "warm up" time is very diffe-
rent for the various elements of your audio system.
Higher and homogeneous sound quality is achie-
ved while keeping the device switched on.
Your audio specialist dealer has enough experi-
ence to give you more information.
Net frequency noise
Some audio source devices may in combination
with the amplifier cause a humming noise at
power line frequency audible from your speakers.
Usually, its volume varies with the volume setting
of the amplifier. This is no sign of a defect or fault
of your audio products but has to be eliminated.
Generally, every wall-powered device connected
to the ground wire of the power plug can cause
this problem when connected to the amplifier.
Experience shows that this problem is mainly cau-
sed by antenna-connected components (as TV-sets
or Tuners), personal computers, electrostatic loud-
speakers, subwoofers, record players or headpho-
ne amplifiers that are connected to the audio
inputs of the amplifier. Another possible reason for
humming noise is electromagnetic interference of
other components’ power supplies with pick-up-
systems of record players (change the place of the
record player for a test).
In most electric devices the ground potentials of all
signals are connected to each other at one central
point, where they have one common connection.
If the device uses the protective conductor of the
wall outlet, the corresponding wire of the line cord
is connected intractably to the metal housing of the
device. In most cases this is the point where the
central grounding point is attached to. By doing
this the housing is able to shield all signals from
external radiated noise. Some main amplifiers are
equipped with a "Ground Lift"-switch. If it is acti-
vated, ground potential of the chassis and the pro-
tective ground wire are being separated from the
central signal ground point. The protective ground
wire keeps its function. Sometimes this helps pre-
vent noise caused by errors in grounding.
If the problem occurs and cannot be solved by
yourself your audio specialist dealer will help you.
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