Entertainment Center: TVs, Stereos, VCRs and DVDs - Subwoofer hum
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bwuce
11-13-07, 05:35 PM
I have another electrical problem. I have a home stereo powered subwoofer that makes a hum when it is turned on. It makes this sound even though it is not connected to the stereo. What could be the problem?
HotinOKC
11-13-07, 07:02 PM
Sounds like interference and/or a bad cable.
Triple check your cables.
Triple check your cables.
Strategery
12-02-07, 09:48 PM
60 cycle hum from the A/C power supply is possible; unless you run off a battery, it's almost impossible to completely remove the 60 cycle hum. Is it really loud, or do you just hear it when you're close? There could be a ground loop, but that's unlikely if it's not connected to something. The amp may be expecting a certain resistance, and by not connecting it the circuit is not quite right. Good luck.
HotinOKC
12-03-07, 03:32 PM
You might want to put that in Laymans terms.
Most people would have no idea what you are talking about.
Most people would have no idea what you are talking about.
Rick Johnston
12-04-07, 03:06 AM
The sub should be silent if it isn't plugged in to anything. Try moving it to a different location in the house to see if there's an electrical field in the old location that might be causing the hum. (It could even be the TV causing it.) If it still hums in the new location, take it back for service or replacement.
eleven22
12-04-07, 09:58 AM
some of the sub woofers have a few control knobs on them because they have amplifiers built into them. many like some of the Bose systems actually power the satellite speakers. You may have the volume or gain raised all the way up. Or high enough to have the speaker make the buzz. You can see this in many musical combo amplifiers as well. Another possibility is that the amp is not grounded properly, but I suspect theory number 1.
Rick Johnston
12-04-07, 03:59 PM
Don't confuse gain with attenuation. The Bose system is expecting to control the volume of the entire system, so it has a preamp stage with gain. The gain stages of musical instrument combos are some of the highest (and noisiest) ever designed for audio. Turn either all the way up, and you'll hear hiss (and buzz, and hum, and spit, and all kinds of other noises).
Amplifiers like those in powered subs are designed to run all the way up all the time with a fixed amount of gain. The volume controls are actually attenuators that reduce the signal at the input so the amp will "gain match" with the others in the system.
A properly working amplifier should be dead silent with nothing plugged in to its input.
Amplifiers like those in powered subs are designed to run all the way up all the time with a fixed amount of gain. The volume controls are actually attenuators that reduce the signal at the input so the amp will "gain match" with the others in the system.
A properly working amplifier should be dead silent with nothing plugged in to its input.