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Audio Systems/3.5 mm external speakers for cell/mp3 player


Hi, First, thanks for taking my question, sharing your knowledge and volunteering.
I just bought a generic battery/5v ac/dc powered plug in speaker system second hand at Goodwill. When I got it home I put in 4 AA as required. I turned on the speakers and they came on but there was a thump thump thump sound in a continuous fast beat pattern. I thought it was strange and perhaps due to weak batteries so I used a 5 volt ac/dc adapter as required and the same thing happened. I then suspected it might be a short in a wire or connection and I thought about taking it apart and checking it but I thought I better ask for advice first. One thing I tried was using a 5.5 or 6 volt adapter and the  steady thump, thump, thump turned into a long hum-m-m (a bit less unusual) The thumping sound is such a strange sound to me, I've never heard a pattern like that before, it's almost as if someone were sending a signal in that it's so regular and constant when the speakers are turned on. Can you give me some advise to try. I dislike this disposable society we find ourselves in, besides I am on a very tight medical handicap income and I can't afford not to try and fix it.
Thank you, Thomas

Did you test the speakers before you made the purchase.  Most Goodwill shops have a place where you can fire them up. I have seem customers bring in power supplies and batteries to check out the electronics before the purchase.  In your case I think the speaker's internal amplifier is defective. Maybe that his why they showed up at Goodwill!

Can you speak to the store?  Sometimes they will let you return them within a  2 week  period.

Sorry you are having this problem.

PS: Usually for powered speakers the power pack must be the dedicated supply because of current requirements.  You could try, perhaps, a power mod with greater current capacity.  

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Audio Design Engineer; systems, loudspeakers, cd/dvd players, etc. I am knowledgeable in all high end audio equipment and installations. MAKE SURE YOU GIVE A MAKE AND MODEL NUMBER AND CAR IF IT IS AN AUTO QUESTION. Note: I am getting some who ask good questions that take a lot of time to research but then the questioner fails to read the answer. Please don't ask questions unless you are seriously looking for an answer. If you find an answer to your question otherwise then let me know with your reply. Thank you.


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