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Power small speakers

Discussion in 'Receivers and amplifiers' started by 21Q, Nov 27, 2011.

  1. 21Q

    21Q Regular member

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    I pulled two small speakers from a laptop. 4ohm 2watt. I was wondering how to power them properly. Im figuring I need 9v total.
    I was going to use them in a set of custom headphones. They work great when plugged into a pc. But when plugged into a mobile device the sound is horrific and I hear no voice. I have it wired both speakers are connected via 1 wire, and both speakers have one wire going to the plugged.

    Any help is appreciated. Im starting to pull my hair on this.
     
    Last edited: Nov 27, 2011
  2. cactikid

    cactikid Active member

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    does not sound right there,left and right would or should have separate feeds as in stereo and you are wiring them up as a mono speaker,if you look at the jack plug on headsets they should have 3 sections,how many have yours,not too sure about the battery as the ones i had an amp built in for the power.
     
  3. Jeffrey_P

    Jeffrey_P Regular member

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    What cactikid said.

    You should have at least three wires. R, L channels and at least one return. The return is the largest conductor closest to the molded part of the connector.

    Use a 9v battery to find out what channel is which. You should get 0 Hz. (DC) noise from each speaker. If that seems to be okay there may be something wrong with the mobile device.

    The impedance is 4 ohms basically for more bass but also having 1/2 the voltage drop compared to an 8 Ohm speaker the output is theoretically 2x.
     
  4. 21Q

    21Q Regular member

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    Hmm. 3 wires. Where would the third come from? I had taken apart a (very) old pair of head and copied that wiring.
    I have it set up like this here
    [​IMG]

    What would I need to change?
    I've been testing it with no power on pc and mobile. On any mobile device it gives me no voice/bad sound.
     
    Last edited: Nov 27, 2011
  5. Jeffrey_P

    Jeffrey_P Regular member

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    Your wiring diagram shows a ground between the two speakers but no ground to the amplifier.
    That won't work unless it's you want a mono output. I suspect one of those two wires is ground. It also changes the impedance. The amp is now looking @ 8 Ohms.

    BTW, have you tried the 9v battery test yet? The test will tell all.

    Jeff
     
    Last edited: Nov 27, 2011
  6. cactikid

    cactikid Active member

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    imagine 2 separate speakers each speaker needs 2 wires - and + feeds thats 4 wires to bring down to 3 the 2 - wires are joined together so you have a circuit to each speaker.that leaves you with 3 connection same as i have on a stereo headphones.
     
    Last edited: Nov 27, 2011
  7. Jeffrey_P

    Jeffrey_P Regular member

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    "imagine 2 separate speakers each speaker needs 2 wires - and + feeds thats 4 wires to bring down to 3 the 2 - wires are joined together so you have a circuit to each speaker.that leaves you with 3 connection same as i have on a stereo headphones."

    Yep, way things are now the speakers are wired in series (mono).

    Have to be careful with 24. 26 and 28 Ga. wires. It's easy to hack one off by accident.
    Decent wire strippers help a lot.

    Jeff
     
  8. cactikid

    cactikid Active member

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    no not like you have in diagram as you have only 2 wires,the 4 wires come up to the jack plug and 2 are twisted together to act as an earth which then leaves 3 wires.sent you a pm also.
     
  9. 21Q

    21Q Regular member

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    Thanks for all the replies. I wasn't able to get a hold of a 9v battery today, so Ill have to save that for tomorrow. Also my 3.5mm plug that i was using broke from bending the pins too much, so I'll have to grab a new one from those.
    I did try to power just one of the speakers with 6v which should still be enough wattage for one speaker, but all it did was puff up and not play any sound. I wired it like this
    [​IMG]


    I'm putting this all into ww2 headphones and these speakers couldn't fit more perfectly than any other speakers I've found. I rewired my set up to look like this
    [​IMG]
    Once I get the new plug I'll try it out.
     
    Last edited: Nov 27, 2011

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