Read JBL GTS 100X User Guide / Operation Manual online
28
Power wires carrying high cur-
rents may induce noise in nearby
signal wires. Make sure that
power wires and signal wires do
not run together for long dis-
tances. When power and signal
leads must cross, they should
cross at right angles. If you sus-
pect that power line noise is
being induced in the signal leads,
you can repeat the test for source
noise described previously, but
perform the test at the amplifier
end of the signal cables.
Other Noise Sources – Common
noise problems will be solved by
proper grounding and power sup-
ply connections. However, there
are many noise suppression
devices (such as spark plug and
coil lead suppressors and rotor
and coil bypass capacitors) avail-
able at auto parts or car stereo
stores. There are also noise sup-
pressors that can be connected
directly to the alternator, which
are effective in some situations.
The use of any such suppressors
should be discussed with a JBL
authorized installation specialist.
Certain vehicles are particularly
“noisy,” especially models that
have solid-state ignition systems
or that have non-metal bodies.
Such vehicles may require elec-
trical noise suppression devices
which are not normally needed.
Antenna – A common noise prob-
lem is generated by a “ground
loop” produced by the antenna
shielded cable being grounded at
both the antenna mounting point
and at the head unit input. In this
instance, insulate the antenna
ground from the chassis of the
vehicle at the antenna mounting
point so the antenna shield is
grounded only at the radio’s
antenna input. Commercial
antenna ground-loop isolators
are also available.
Switching Noise – The GTS100x
has a highly developed switching
power supply which generates
some RF interference as a result
of its switch-mode operation.
Although this is internally filtered
and shielded by the GTS100x
chassis, some unusually sensitive
installations may pick up switch-
ing noise, especially when listen-
ing to weak AM radio stations. If
this unusual situation occurs, one
of the following installation cor-
rections will typically eliminate
the problem. 1) Relocate the
amplifier to a position farther
GTS100x OM 7/16/98 2:56 PM Page 28
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