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How do I give my speakers more power? Answered

I recently took apart an old boom box and salvaged 4 working speakers out of it. Then, I thought it would be fun to mount them in my workshop so I could plug in my ipod and listen to music while I work. I've tested them out and they all worked when I connected the leads to wires from an old pair of headphones. The only problem is there not very loud, so I would like to give them some more power but I'm not sure how to do that. Two of them say 8ohm 3w, on the back and the other 2 say 8ohm 5w, and then I have another random speaker that says 2w, 8ohm, 4w max. So, how much power can those speakers handle (in volts and amps) and how do I hook them up? Can I just connect them in series with a wall wart and my ipod or do I need to build some sort of amp?

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Punkguyta (author)cannedham1602009-02-03

Although small speakers from a boom box like that are good for little projects where you need some cheap audio shoved in somewhere. But for just tinkering around in the workshop with some tunes, you'd probably be better off buying a cheap used stereo from a yard sale. If I were you, I would either save the speakers for a project, or play around with them/see what kind of voltage it takes to burn the coils :P Have ya ever seen a car subwoofer plugged straight into the wall socket?

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Sandisk1duo (author)Punkguyta2009-02-04

why ruin a woofer if you can sell it?

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11010010110 (author)Sandisk1duo2009-02-04

why ruin a woofer if you can USE it?

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Sandisk1duo (author)110100101102009-02-04

well if you don't have an Amp...

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11010010110 (author)Sandisk1duo2009-02-04

get / build one ! for loud and not perfect bass i think you can just use a power transistor and txformer

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Sandisk1duo (author)110100101102009-02-04

i've tried... you mean like a push-pull amp?

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11010010110 (author)Sandisk1duo2009-02-04

yep even simpler and inefficient dc-to-transformer amp

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Sandisk1duo (author)110100101102009-02-04

wanna give me a schematic?

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Sandisk1duo (author)110100101102009-02-04

do i really need the transformer?

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11010010110 (author)Sandisk1duo2009-02-04

preferred. the transformer passes a lot of dc which make it and the transistor heat up (transistor gets really hot and requires big cooler) without transformer the speaker would take the heat itself a dc filtering capacitor may or may not work this circuit is very inefficient and does not give too good quality. use push pull or other real amp if possible

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Sandisk1duo (author)110100101102009-02-04

i have some nice 40W transistors with hFE of 15-30 how about a schematic for push-pull?

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11010010110 (author)Sandisk1duo2009-02-04

those are nice but you have to find out yourself all values of components and maybe limit the current somehow never built a push pull i built some single-chip amps (the amps i like the most) and one amp like this (that i call dc to transformer)

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Sandisk1duo (author)110100101102009-02-04

the thing is, that with push-pull, you need a positive, a negative and a ground i'm a little stumped on how toy biuld that...

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11010010110 (author)Sandisk1duo2009-02-05

you dont need positive and negative. just a dc filtering capacitor there is also push pull with 2 identical transistors based on the dc circuit. its as good as any other push pull. but the opamp part is a bit more complex

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Sandisk1duo (author)110100101102009-02-05

i have two complimentary transistors, and some op amps

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11010010110 (author)Sandisk1duo2009-02-05

thats good but i have no byte how to make a push pull from them

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11010010110 (author)2009-02-03

you have to use an amp you can use the existing amp of the boombox. connect the speakers back to it and feed the input from the ipod to the cd / aux inputs (if there are) or instead of the head in the tape deck you can also find amps in other devices if you really want to add that extra speaker a wall wart gives electricity but it does not contain sound (maybe except electrical hum). if you connect it to the speakers it will make them heat more and maybe add hum to the music but it won't amplify the music. you can also damage the ipod

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cannedham160 (author)110100101102009-02-03

well that would have worked, but I got a new solder sucker awhile ago and needed something to try it out on. So, needless to say the original boom box is now missing several resistors, transistors, and capacitors. What if I wanted to make something similar to an Altoids amp only with an ac adapter of some sort so I could plug it into the wall, is that possible?

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11010010110 (author)cannedham1602009-02-03

if its supposed to give output to speakers then sure search for existing stuff with amp look into amplifier chips - there is TDA2002 that can give 8 W power and does not require much other components to work

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cannedham160 (author)110100101102009-02-03

if I could find the amplifier chip on my boom box would I be able to use that chip with some of the other components form the boom box to make a new amp in a different case?

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Does anyone know how I can identify the amp chip on the circuit board of my boom box? Does it have a special code on it or other special markings?

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11010010110 (author)cannedham1602009-02-04

trace where the wires from the speakers goto. in most amplifiers the speaker is connected in series with a big capacitor right to the output of the amplifier in some boomboxes the amplifier is built of distinct components on the board and not a chip

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cannedham160 (author)110100101102009-02-04

I think I've found my amp chip, I'm thinking it's either the black chip with the heat sink or the black chip in the other pic. What do you think?

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11010010110 (author)cannedham1602009-02-05

no. amp chips have 5 entries or more and not 3 this may be the part of the amp though. if you did not remove components from the area close to the speaker output the amp may still be functional

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