Filter
Top Products
22
User's Manual
User's Manual
User's Manual
User's Manual
Hum
Adding any component such as a sub-
woofer to an existing system will often
give rise to a hum which wasn’t there
before. Your rst thought may be that
the subwoofer has a problem, but this is
more than likely caused by a “ground-
loop” in your system.
Follow these steps to isolate the main
cause of the ground-loop hum (there may
even be more than one cause).
• Try to have all of your equipment on
the same electrical outlet or circuit, see
page 10 for more details.
• If your subwoofer is a fair distance away
from your other equipment, you may use
a 15 amp extension cord as long as it
has a ground connection.
NOTE: Never remove the ground
pin from any power cords. This is
very dangerous.
• Turn off all components in your system,
including the subwoofer, ampliers and
the preamplier, before disconnecting or
connecting cables.
• First remove every connection from the
subwoofer to the rest of your system.
Plug the subwoofer power cord back in
and check for the hum. If it is still there,
try plugging it into a different outlet in
case it is picking up interference on the
AC line.
• If you have followed the above guide-
lines for the power connections and a
hum is still present, then there is one
very common problem to consider: a
“ground-loop” introduced by connecting
a cable TV line to a VCR or TV, which is
then connected to the preamp. This can
be addressed as follows:
• Disconnect all cables which come from
outside the room, such as cable TV,
satellite TV, or roof top antennas. Make
sure that they are disconnected where
they rst enter the room, so they are
making no connection to your
preamplier, TV, or any other compo-
nent. If the hum is caused by the cable
TV line, then you will need a “ground-
loop isolator.” This is an inexpensive
device tted in line with the coaxial cable
feed.
• If the hum persists, disconnect all the
source components one at a time from
the back of the preamplier until you
identify the problem.
• Ground-loop isolators are available for
audio lines and video. Once you have
identied which components are causing
a problem, you can t the isolators be-
tween the component and the preampli-
er.
No Auto Turn-off
• The subwoofer should go into standby
mode after approximately fteen min-
utes with no audio signal present. If not,
check there is no background hum. The
subwoofer may sense hum as a small
signal and stay on. See the above hints
to eliminate the hum.
No Auto Turn-on
The subwoofer should turn on (come out
of standby mode) when an audio signal
is applied, or 12 VDC is applied to the
Trigger inputs, or if the Start button is
pressed. If it does not then, check the
following:
• Check that the subwoofer power switch
is on.
• The subwoofer’s volume control may
be turned down, or no signal is received
from your preamplier.
• Check the input connections.
• Check the mode switch or menu on sur-
round systems to be certain that a bass
signal is being sent to the subwoofer.
• Use the 12V Trigger for the most reliable
on/off operation.