Bad caps in cheap computer speakers

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  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK
    #21
    Re: Bad caps in cheap computer speakers

    I left all my storage of caps at home.

    Checked prices for 4700u and they are more expensive than 6800u, because min order 5 for the 4700u. I will check 3300u too.

    I also plan to upgrade the amplifier to some kind of class-D in the future, possibly of my own design based on discrete FETs.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

      Comment

      • lti
        Badcaps Legend
        • May 2011
        • 2547
        • United States
        #22
        Re: Bad caps in cheap computer speakers

        A TDA2822M (or the TDA2822N, which appears to be identical) doesn't need coupling caps on the input.

        Also, that is a really lame transformer. I would upgrade it along with the filter caps. With that chip, the only way to eliminate power supply noise on its output is to power it with a linear voltage regulator.

        What speakers are these?

        Originally posted by mariushm
        Why don't you just use a TDA1308?

        Datasheet:
        How good is that chip? My computer uses a cheap clone of the TDA1308A for its headphone output.

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK
            #23
            Re: Bad caps in cheap computer speakers

            Well, upgrade complete. Pictures later.

            6800uF (Panasonic - but just general purpose) now means that playing ordinary audio, nominal voltage is about 12.5V. No audio nominal is 14.5V, like before (a little higher because of less ripple.) Speakers will now play ordinary music for about 5 seconds before cutting out - so it's got quite a bit of headroom!

            Didn't bother to upgrade the output coupling caps, may do that at some point with smaller caps. Then again, I may make my class-D board at some point, which will use BTL so no need to upgrade coupling caps just yet.
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

              Comment

              • Logistics
                Badcaps Veteran
                • Apr 2007
                • 721
                • USA
                #24
                Re: Bad caps in cheap computer speakers

                I would just change the output coupling caps to bipolars and cross them with .1uF films.
                Presonus Audiobox USB, Schiit Magni 3, Sony MDR-V700

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