I just installed a 500 watt home theater sound system. The unit makes a steady hum while turned on.?

Question

What could that be and what can I do about it. Thanks.

Answer 1

Probably picking up interference from a high voltage line.  Make sure all speaker wires are at least 12 inches away from any 110v power outlets/lines in your house.  If the speaker wires were pre-wired, whoever did it, should've not run them around any high voltage power.

Answer 2

There are several sources of hum in a system.

Try this: turn the system on so you hear the hum.  Disconnect your main CATV cable. If the hum stops, call your cable company and have them come out and ground the cable outside your house.

If that is not the problem, get a 2-prong to 3-prong adapter and use this on the self-powered subwoofer. If this solves the problem, do not leave it like this. Instead, go out and buy a "Subwoofer" cable with little arrows on it showing the signal direction.

These Subwoofer cables do not have the shield connected on one side and this breaks the ground loop.

The other thing is to make sure your speaker wires are separated from power wires.

You want 3 bundles of wires in back of your rack:

- AC Power wires

- Speaker wires (which ARE power wires)

- Interconnects.

I always recommend putting the receiver on the lowest shelf so speaker wires flow out & away from everything else.  I bundle the AC power cords to 1 side and the entire center of the rack is free for the interconnects.

Answer 3

Could be interference from another device. Also make sure the speakers are connected correctly regarding polarity. Red to Red etc.