Sunfire True Subwoofer Signature and Standard Version user manual The subwoofer won’t turn off

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 Þrst 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, ampliÞers and the preampliÞer, 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 Þrst enter the room, so they are making no connection to your preampli- Þer, TV, or any other component. If the

hum is caused by the cable TV line, then you will need a “ground-loop isolator.” This is an inexpensive device Þtted 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 preampliÞer until you identify the problem.

•If you are using the subwoofer’s line level inputs and there is a excessive amount of noise or hum present, using the speaker level inputs may yield a lower background noise level.

•Ground-loop isolators are available for audio lines and video. Once you have identiÞed which components are causing a problem, you can Þt the isolators be- tween the component and the preampli- Þer.

The subwoofer won’t turn off

•The subwoofer should turn itself off after approximately Þfteen minutes 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.

The subwoofer won’t turn on automatically

The subwoofer should turn on when an audio signal is applied, or 12 VDC is ap- plied to the Trigger inputs, or if the Start button is pressed. If it does not turn on, check the following:

•The subwoofer’s volume control may be turned down, or no signal is received from your preampliÞer.

•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.

22 User's Manual