Why DSL filters go bad over time

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  • japlytic
    Badcaps Legend
    • Oct 2005
    • 2086
    • Australia

    #1

    Why DSL filters go bad over time

    In an old ADSL filter which was not adequately filtering out noise on the phone line at a client's house was a 1uF 100V Jun Fu bipolar electrolytic capacitor.

    I recommend against using aluminium electrolytic capacitors in DSL filters, because they can deteriorate over time, even the good ones. But you can't tell if they have electrolytic capacitors unless you open them (and void the approval).
    Good filters have polyester or polypropylene and sometimes tantalum (still a good choice) capacitors inside.

    The largest non-electrolytic capacitor I have seen in a DSL filter was a 1uF 63V polyester unit.
    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.
  • Scenic
    o.O
    • Sep 2007
    • 2642
    • Germany

    #2
    Re: Why DSL filters go bad over time

    Jun Fu? no wonder..
    they always dry out.. even from just sitting around unused..

    Comment

    • Junk Parts
      Court Jester
      • Jun 2006
      • 8953
      • USA

      #3
      Re: Why DSL filters go bad over time

      I have a brand new ADSL filter on my phone that does almost nothing to block the DSL noise. Going to have to get under the desk and change it out.
      "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so."
      Mark Twain

      "I wish to have no connection with any ship that does not sail fast; for I intend to go in harm's way."
      John Paul Jones

      There is a fifth dimension, beyond that which is known to man. It is a dimension as vast as space and as timeless as infinity. It is the middle ground between light and shadow, between science and superstition, and it lies between the pit of man's fears and the summit of his knowledge. This is the dimension of imagination. It is an area which we call the Twilight Zone.
      Rod Serling

      Comment

      • stj
        Great Sage 齊天大聖
        • Dec 2009
        • 30952
        • Albion

        #4
        Re: Why DSL filters go bad over time

        tantalum is polarised, and "very" sensitive to reverse current.
        it would be insanely stupid to use one inplace of a bi-polar device unless your trying to start a fire.

        Comment

        • Uranium-235
          Comrade Glimmer
          • Aug 2007
          • 5042
          • US

          #5
          Re: Why DSL filters go bad over time

          or you could just go with cable. for an extra $10-15 a month you dont' have to deal with this crap. of course its not available everywhere I know.

          but if you have cable available in your area, please use it, thank you.
          Cap Datasheet Depot: http://www.paullinebarger.net/DS/
          ^If you have datasheets not listed PM me

          Comment

          • ratdude747
            Black Sheep
            • Nov 2008
            • 17136
            • USA

            #6
            Re: Why DSL filters go bad over time

            cable is not a solid connection... it peaks... but, it is worth it if is not too pricey

            i have always heard you should change the filters yearly as they do go bad... i used to have it in my old house, but we have cable here at the new house (no dsl here as the phone lines are too old).
            sigpic

            (Insert witty quote here)

            Comment

            • severach
              Badcaps Legend
              • Aug 2007
              • 1055
              • USA

              #7
              Re: Why DSL filters go bad over time

              The caps in my filter look like polyester.
              sig files are for morons

              Comment

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