Altec Lansing 251 buzzing sound

drtanz

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I have the Altec Lansing 251 speaker setup, and once I switch them on there is a loud buzzing sound, even when not connected to my Mac. The sound starts when I connect the right front speaker, and stops when I unplug it from the back of the subwoofer. Any ideas what might be causing this?
 

everlost

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corrosion on the volume/balance knobs or jacks.
failing filter/amplifier circuit or sound card(capacitors/inductors/ICs).
broken ground wire.

try it on another device, like an MP3 player or another PC.
 

drtanz

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The speakers make the sound when not connected to anything.
 

everlost

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yes, but if its ground wire related, it could stop on another playback device. this would only be a small step in trouble shooting. if it is ground or ground loop problem, it could be related to any wire in your speakers/amp/pc/wall giving you trouble.

also touching the jackk with your finger may stop or amplifiy the humming. stoping would usually mean a ground related problem, while louder hum may be filter or amp problem.
 

drtanz

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Tried connecting to other devices and still the same.

I can't really touch the jack with my finger, because if it's connected it makes the sound, and as soon as I disconnect it from the subwoofer the sound stops, so it wouldn't make a difference at that point.
 

everlost

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the front right speaker to sub connection is 9pin jack?
if that is so, then disconnecting that jack isolates everything from everything else, and turns it off. i was refering to the 3.5mm jacks (probably black, yellow and green), and come from the sub/amp.
 

drtanz

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Yes that is correct, it's a 9pin jack and appears to do what you described.
 

everlost

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if you touch the 3.5mm jack ends with your finger does the buzzing stop?

have you tried pluing the speakers into another room/circuit?
can you plugit into the wall upside down? if i recall its a 2 prong plug, but might be keyed so you cannot do this. if you can does the buzz stop?
 

drtanz

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If I touch the 3.5mm jack ends the buzzing does not stop. I tried connecting the system to several other circuits around the house with the same effect. It's a 3 prong plug so it goes in one way only.
 

everlost

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well, you did all you can do to rule out ground loop. all that is left is dirty power or failed amp. dirty power can be caused something in your home or by the utility. in your house things like CFL/LED lighting, battery chargers, and motors.

CLFs and LEDs can put noise on the line when they are on, dimmers for this lighting can do this even when off.

battery chargers, cell phone adapters, and anything that turns AC to DC wil do the same. but you would need hundreds watts worth to cause trouble, or a few failed adapters. they would be excessively warm to the touch and batterys would take longer to charge. this could also be a symptom of trouble on the utility side.

then there could be a problem with your homes wireing. this would have been giving you trouble from the first day. you eliminated a single circuit fault so if there is trouble it would be at the main panel.

to fix these problems you would have to contact your electric utility, or an electrician to look over your wireing and connections. you could look into picking up a power line conditioner, you can get on at your local Audio/video shop.

or your amp/preamp is failing on your speaker system. any of the above would not fix this
 

thee_prisoner

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Good advice by everlost but ground loop problems are a humming sound(also mentioned by everlost) in the 50-60Hz range. So is it a buzz or hum? Many times it is a TV and/or the cable ground from the cable company causing the problem. An easy and cheap way is to isolated the problem by going to a 2 prong plug. Don't connect the green wire if it has one. Basically saying you might have 2 ground points, one different from the house ground and one different from the cable ground.

Is this a new occurrence or did this start happening when maybe you added a new device to the wall circuit or powerstrip?

If the problem still exists, after trying different combinations, you might need to add an isolation transformer type plug to stop it. It could be dirty power but if it is a new thing, probably not.

 

drtanz

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I can try a two pronged plug, can I just use an adapter from 3 to 2 prongs? I've had this sound system for more than 10 years and I don't recall it used to do this before, although I did use it on and off as I sometimes spend up to a year abroad. I tried it at different power points around my house, which seems to eliminate the issue regarding new plugs added to the circuit or power strip.
 

thee_prisoner

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3 to 2 will work, but it has to been plugged into a wall socket not a power strip to isolated it. Did you move into a new place when you tried it out? Once again, is it a hum or a buzz?

The fact that is works in some circuits and not others sounds like some kind of interference. Try turning off everything except the devices for the computer and speakers(everything in the home).
 

drtanz

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To clarify, the sound is a hum and trying it in various sockets around the house resulted in no difference, humming sound at same intensity at each power point.
 

thee_prisoner

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Did you try unhooking your internet cable from your computer like I suggested above that may be a ground loop problem?

If you have access to some other speakers and it sounds fine then it's most likely the speakers, otherwise it's back to figuring out what is the problem.
 

drtanz

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I tried the speakers on their own, without connections to any computer or device, at various points around the house, and I still get the hum.
 

thee_prisoner

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Since it is happening all over the house, like I suggested is to disconnect the cable from anything in the house. If that doesn't work it could be the speakers, the only way to tell is try taking the speakers to a different house. IT could be the amp is going bad in the speakers.

And just to repeat myself "Many times it is a TV and/or the cable ground from the cable company causing the problem. An easy and cheap way is to isolated the problem by going to a 2 prong plug. Don't connect the green wire if it has one. Basically saying you might have 2 ground points, one different from the house ground and one different from the cable ground.

If the problem still exists, after trying different combinations, you might need to add an isolation transformer type plug to stop it. It could be dirty power but if it is a new thing, probably not.

the Prisoner...
 
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