converting a portable speaker battery powered system to plug in ac power

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Old 12-21-10, 07:31 PM
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converting a portable speaker battery powered system to plug in ac power

i bought a portable speaker system an i want to change it from being powered by 3 aaa batteries to regular house ac power and i was wondering how i might do that without frying the speakers/circuits?
thanks
 
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Old 12-21-10, 07:47 PM
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Well you are looking at something that will power 4.5 volts and what ever amp or milli amp draw. DC to DC.

Something like this but there are many out there.

12 volt to 1.5, 3, 4.5, 6, 7.5, 9 volt switching DC/DC converters with 2 amp output car adapter.

Mike NJ
 
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Old 12-21-10, 08:33 PM
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im looking to make something preferably. like how would i make an adapter like that or what could i salvage to make one of those
 
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Old 12-21-10, 08:38 PM
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Dont be cheap.. They are less the $20.........

Mike NJ
 
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Old 12-21-10, 08:42 PM
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dude this is a diy website plus i only payed $12 for the speakers so i dont want to spend anymore than $10 to get it ready
 
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Old 12-21-10, 09:15 PM
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Since you've posted on a DIY site, you should give building your own power supply a try. All it requires electronically is a transformer (120 to 5v, but up to 12v will work), a bridge rectifier, a 7805 voltage regulator and a couple of filter caps. This project should be able to be done for around $20 in parts including the case and connectors.

[Edit - you posted as I was posting. You can scrounge these parts from other devices that have died around the house.]

Here is a very good illustration. The only difference between my suggestion and the site's is their use of four diodes to make the bridge rectifier. These diodes are available as a single component.

You will hear a slight hum in the speakers. Increasing the value of the 220uf caps can help.

Don't worry about the fact that three 1.5 volts batteries equals 4.5 volts and you'll be feeding it 5. The electronics in the speaker will tolerate wide voltage swings, and this is only 10%. (Think about what happens when those batteries die. The speaker continues to play at 4 volts, then 3 ...)
 

Last edited by Rick Johnston; 12-21-10 at 09:18 PM. Reason: Add edited section
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Old 12-21-10, 09:19 PM
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OK ............I am just saying the time and effort you put in for $10 more.... done. DIY?? you asked for advice and this is in your best intrest. Stuff, (off the shelf) for what you want is cheap these days but it does not pay to fabricate....

Yes you can find a DC regluator that produces same amps and voltage... but why when they have them? Your not saving money...

Do what you want. Make it for $20 OR BUY IT FOR $20

Mike
 

Last edited by lawrosa; 12-21-10 at 09:41 PM.
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Old 12-21-10, 09:30 PM
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thanks rick for the advice and it wont cost me $20 because i already have all the parts
 
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Old 12-22-10, 05:52 AM
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Lawrosa, sometimes the gratification that comes with building something is worth more than money. Plus, every time I build something I learn something.
 
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