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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


4 posters

    cap gone bad?

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    colin86325


    Posts : 61
    Join date : 2014-04-01

    cap gone bad? Empty cap gone bad?

    Post by colin86325 Sat Sep 06, 2014 8:56 pm

    Pretty sure this bulge is not usual, but wanted to confirm.

    cap gone bad? 20140906_203520


    cap gone bad? 20140906_203252_resized
    sKiZo
    sKiZo


    Posts : 1530
    Join date : 2013-04-01
    Location : Michigan USA

    cap gone bad? Empty Re: cap gone bad?

    Post by sKiZo Sat Sep 06, 2014 11:13 pm

    Ceramic gumdrops, especially older ones, weren't always the prettiest components. I imagine it didna look much better when it was shiny new. You'll usually see either cracking or burning when one overloads, and they don't tend to drift much over time.

    It's bulging in electrolytics that you have to worry about.

    Easy enough to test if you have a VOM that does capacitance, but you'd need to remove it from the circuit to get an accurate read. Most good VOMs will also have special short leads to minimize read errors.

    PS ... is that normal on that amp, or a bypass mod?
    Roy Mottram
    Roy Mottram
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    Join date : 2008-11-30

    cap gone bad? Empty Re: cap gone bad?

    Post by Roy Mottram Sat Sep 06, 2014 11:46 pm

    "orange drop" caps are dipped in a plastic liquid coating and it doesn't always dry evenly, it's likely a good cap unless you hear or measure something wrong.
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    colin86325


    Posts : 61
    Join date : 2014-04-01

    cap gone bad? Empty Re: cap gone bad?

    Post by colin86325 Sun Sep 07, 2014 11:16 am

    Thanks guys, I guess I will test it to see.

    This is actually on the Dynaco amp i bought a few months back.
    Dynalover
    Dynalover


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    cap gone bad? Empty Re: cap gone bad?

    Post by Dynalover Sun Sep 07, 2014 1:41 pm

    That's an older version of a Sprague "orange drop", one of the better quality capacitors around. Poly film, it is almost certainly OK. You can use a modern capacitance tester to check for value, but they will not test for leakage at meaningful voltage ratings. I wouldn't worry about that one, however.

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    cap gone bad? Empty Re: cap gone bad?

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