PSA GCC-500 - Manual (Page 16)

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Troubleshooting 12
®
Troubleshooting
©2004 PS Audio International Inc. All rights reserved.
Owner’s Reference GCP Stereo Preamplifi er
If you experience a hum through the speakers this can be caused by several things. The fi rst is the
source. If there is an excessive amount of buzz or noise from the loudspeaker, it may be caused by a
ground loop, a light dimmer in the home, poor AC power, or any number of causes. The quickest way
to determine where to start your search is to simply turn the amp off, disconnect the cables feeding
its input, and see if the hum goes away when you turn it back on. If it does, it’s most likely a ground
loop or buzz from a dimmer.
The easiest way to fi gure out where ground loop problems lie is by the process of elimination. You
need to determine where the hum or buzz is coming from within your system.
If the hum/buzz goes away when you remove the inputs to the GCC Control Amp, your next step will
be to reconnect the sources, one at a time, listening for the return of the hum. After each connection,
check for hum until you discover
the humming culprit.
VCR’s, surround processors, and
any device that is connected to
a television cable or satellite dish
can cause a loud buzz and should
always be suspect. If, by the process
of elimination described above, you
determine it is a component like a
VCR that is causing the hum/buzz
to occur, and using a cheater plug
or removing the ground pin on a PS
xStream Power Cable doesn’t help
matters, it may be necessary to
isolate the cable connection (CATV)
with an isolation transformer. This
inexpensive device is available at
most Wal Mart, Radio Shack or
department store type outlets and is sometimes called a ‘matching transformer’. If you have problems
fi nding one, call your local cable TV company for advice. The matching transformer will be placed
between the cable TV cord and the VCR, TV or processor.
Just remember, take the system down to its simplest level of connection. Find a way to hook the
system up with as many pieces of the system missing or not connected. Keep it simple and get it
to the point where the hum’s gone. Then start adding back components one at a time until the hum
returns.
Finding the problem is 9/10th of the work of fi nding a solution.
If the blue light is too bright, or if it is not lit but the amplifi er plays, check the rear panel of the GCC
Series Power Amplifi er for the three position dimmer switch. The switch is located on the rear panel,
upper left hand side as you face the rear of the unit.
Finding a ground
loop
Try a cheater plug
Process of
elimination
It could be the
cable TV
Blue light is too
bright
If you have hum
or buzz