Question about DC powered electronics.

Discussion in 'The Projects Forum' started by duhdave, Feb 6, 2013.

  1. duhdave

    Thread Starter New Member

    Dec 6, 2010
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    Hello all!

    I'm interested in putting together a basic portable speaker system, but my knowledge of circuitry is only pretty rudimentary.

    I wanted to use a mini amp in combination with some bookshelf speakers, and my question is if it is possible to run this: http://www.amazon.com/LP-2020A-Lepa...6OTI/ref=sr_1_1?ie=UTF8&qid=1360165681&sr=8-1 on a DC battery such as this one: http://www.amazon.com/UPG-Security-...SCWI/ref=sr_1_5?ie=UTF8&qid=1360166194&sr=8-5

    The rear of the amp looks like this: http://ecx.images-amazon.com/images/I/61zBx9b5cJL.png and is powered by a 12V2A adapter.

    Is it that simple to bypass the AC/DC adapter and power it directly from a battery? Or is additional circuitry involved?

    Thanks!
     
  2. BillB3857

    Senior Member

    Feb 28, 2009
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    It should be no problem as long as you are VERY SURE to observe polarity when making the connection. How do you plan to recharge the battery?
     
  3. duhdave

    Thread Starter New Member

    Dec 6, 2010
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  4. BillB3857

    Senior Member

    Feb 28, 2009
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    The run time would depend upon how loud you play your music. The louder you play, the shorter the run time. You may be able to find discharge curves for your specific battery from the manufacturer. You do realize the battery voltage will drop as it discharges. The amplifier may or may not like running at reduced voltage.
     
  5. duhdave

    Thread Starter New Member

    Dec 6, 2010
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    Is there any way to build an external circuit that will boost the voltage?
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
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  7. duhdave

    Thread Starter New Member

    Dec 6, 2010
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    I have read a few, but I'm not ready to make a purchase yet by any means.

    Is there something that I should know about?
     
  8. BillB3857

    Senior Member

    Feb 28, 2009
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    Just curious as to whether you had seen some of the problems mentioned in the reviews such as needing more than a 2 amp supply. Not saying it wouldn't run on 2A, but some found it deficient.
     
  9. Audioguru

    New Member

    Dec 20, 2007
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    The ICs used are from Tripath who are bankrupt because the ICs could not produce their rated output and maybe because the ICs fail soon.

    The amplifier is no-name-brand so it will probably fail soon and the replacement IC is not available anymore. Don't buy it.

    I can't remember its output power but it might be 5W per channel into 4 ohms or 3W into 8 ohms. Look at its datasheet to see the REAL power before there is a lot of distortion.

    You do not play continuous tones at full blast so the current will not be very high.
    Oh, acid rock is almost continuous noise so the current will be very high.
     
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  10. duhdave

    Thread Starter New Member

    Dec 6, 2010
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  11. Audioguru

    New Member

    Dec 20, 2007
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    Nobody (NOT EVEN THE IMPORTER, Pyle) knows which Tripath ICs it uses.
    Its spec's are not detailed.
    It might produce 14W per channel into 4 ohms with a 13.2V supply or 11.5W with a 12V supply. It might produce 21W per channel into 2 ohms with a 12V supply. It might produce 45W per channel into 2 ohms with a 14.4V supply and a momentary saturated square-wave input (not music).

    The output is probably 6W per channel into 8 ohms with a 12V supply.
    Beware, it uses obsolete Tripath ICs.


    The little speakers will work fine with that amp but will produce hardly any bass.
     
  12. duhdave

    Thread Starter New Member

    Dec 6, 2010
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    I see.
    Do you have any suggestions for an inexpensive amp that will drive these speakers?
     
  13. Audioguru

    New Member

    Dec 20, 2007
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    It is difficult to find an inexpensive amplifier because they lie about the amount of output power. Select a name-brand.

    The power must be spec'd for each channel, the speaker you will use (8 ohms), with a certain supply voltage and with a specified low distortion.

    45W into 8 ohms is 54V peak-to-peak and the amplifier will use a 60V power supply voltage or plus and minus 30V.
     
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