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Re: [Electronics_101] 6v DC to 1.5v DC conversion

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  • Jim H
    Hi Again, I got a LM317 voltage regulator and it is powering the mp3 player. However I am getting a high pitched whine which I¹m guessing is some kind of
    Message 1 of 25 , Nov 4, 2008
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      Hi Again,

      I got a LM317 voltage regulator and it is powering the mp3 player. However I
      am getting a high pitched whine which I¹m guessing is some kind of signal
      noise. I¹ve got a 1uF Electrolytic between Vout and Grnd of the LM317 and a
      100nF ceramic capacitor between Vin and Grnd but they don¹t seem to be
      making any difference. Am I using the wrong capacitors? My power source is a
      5v power supply from an old Zip drive.

      Any suggestions greatly appreciated.

      Jim



      From: Jim H <jimh@...>
      Reply-To: <Electronics_101@yahoogroups.com>
      Date: Mon, 03 Nov 2008 17:06:13 +0000
      To: <Electronics_101@yahoogroups.com>
      Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion




      Patrick ­ that sounds just like what I need ­ just off to get one and try it
      out.

      Thanks a million.

      Jim

      From: "Patrick A. Timlin" <ptimlin@... <mailto:ptimlin%40yahoo.com> >
      Reply-To: <Electronics_101@yahoogroups.com
      <mailto:Electronics_101%40yahoogroups.com> >
      Date: Mon, 3 Nov 2008 08:19:53 -0800 (PST)
      To: <Electronics_101@yahoogroups.com
      <mailto:Electronics_101%40yahoogroups.com> >
      Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion

      The often mentioned (in this group) LM117/317 linear regulator is a good
      choice. You can regulate down to 1.25V as long as you have at least 3V
      across the input & output of the regulator (which you do). Also your MP3
      player is probably low current, so you could probably easily use a standard
      TO-220 package (three legs with the metal tab) without requiring a heat sink
      other than the built in metal tab.

      A couple resistors to set the output voltage and maybe a couple filter caps
      if your supply is noise or a switching supply.

      That's about it.

      Patrick Timlin

      http://www.geocities.com/ptimlin/

      > .
      >




      [Non-text portions of this message have been removed]
    • leon Heller
      ... From: Jim H To: Sent: Tuesday, November 04, 2008 12:00 PM Subject: Re: [Electronics_101] 6v DC to 1.5v
      Message 2 of 25 , Nov 4, 2008
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        ----- Original Message -----
        From: "Jim H" <jimh@...>
        To: <Electronics_101@yahoogroups.com>
        Sent: Tuesday, November 04, 2008 12:00 PM
        Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion


        Hi Again,

        I got a LM317 voltage regulator and it is powering the mp3 player. However I
        am getting a high pitched whine which I¹m guessing is some kind of signal
        noise. I¹ve got a 1uF Electrolytic between Vout and Grnd of the LM317 and a
        100nF ceramic capacitor between Vin and Grnd but they don¹t seem to be
        making any difference. Am I using the wrong capacitors? My power source is a
        5v power supply from an old Zip drive.


        The PS is probably a switcher, they can be noisy.

        Leon
      • Jim H
        Hi again If I try a different regulated AC/DC adaptor I still get the same noise. Both power supplies are heavy transformer types so I don¹t think they¹re
        Message 3 of 25 , Nov 4, 2008
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          Hi again

          If I try a different regulated AC/DC adaptor I still get the same noise.
          Both power supplies are heavy transformer types so I don¹t think they¹re
          switchers. Is there any simple way to filter or cut out the noise?

          Jim



          From: leon Heller <leon355@...>
          Reply-To: <Electronics_101@yahoogroups.com>
          Date: Tue, 4 Nov 2008 12:07:19 -0000
          To: <Electronics_101@yahoogroups.com>
          Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion


          The PS is probably a switcher, they can be noisy.

          Leon
          > .
          >




          [Non-text portions of this message have been removed]
        • Jim H
          Hi, I just tried a different mp3 player and there¹s no noise at all. I guess it¹s just something to do with the mp3 player¹s internal makeup. Anyway, it¹s
          Message 4 of 25 , Nov 4, 2008
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            Hi,

            I just tried a different mp3 player and there¹s no noise at all. I guess
            it¹s just something to do with the mp3 player¹s internal makeup. Anyway,
            it¹s fine with a different player so all¹s well that ends well!

            Thanks for all your help.

            Jim

            From: leon Heller <leon355@...>
            Reply-To: <Electronics_101@yahoogroups.com>
            Date: Tue, 4 Nov 2008 12:07:19 -0000
            To: <Electronics_101@yahoogroups.com>
            Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion

            The PS is probably a switcher, they can be noisy.

            Leon


            [Non-text portions of this message have been removed]
          • Steve
            The player (headphone) ground will most likely be switched at a high rate between battery negative a positive in order to double the battery voltage for the
            Message 5 of 25 , Nov 8, 2008
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              The player (headphone) ground will most likely be switched at a high
              rate between battery negative a positive in order to double the
              battery voltage for the player use. So if you try to tie one side of
              the battery input to ground, you are iether shorting out the switcher
              or getting audio plus switcher voltage to your amplifier input. ie
              the battery is not "grounded", it is not zero zolts AC.

              But there are others ways (inductors) to boost 1.5V which may indeed
              connect one side of the battery to ground, would then work with your
              plan.

              LM317 is OK if you are using AC power but inefficient if you were
              running from batteries.

              Simple switchers are not ideal for low voltage. For < 12V input you
              should use a "synchronous" buck regulator to avoid diode losses.


              STeve


              --- In Electronics_101@yahoogroups.com, Jim H <jimh@...> wrote:
              >
              > Hi,
              >
              > I just tried a different mp3 player and there¹s no noise at all. I
              guess
              > it¹s just something to do with the mp3 player¹s internal makeup.
              Anyway,
              > it¹s fine with a different player so all¹s well that ends well!
              >
              > Thanks for all your help.
              >
              > Jim
              >
              > From: leon Heller <leon355@...>
              > Reply-To: <Electronics_101@yahoogroups.com>
              > Date: Tue, 4 Nov 2008 12:07:19 -0000
              > To: <Electronics_101@yahoogroups.com>
              > Subject: Re: [Electronics_101] 6v DC to 1.5v DC conversion
              >
              > The PS is probably a switcher, they can be noisy.
              >
              > Leon
              >
              >
              > [Non-text portions of this message have been removed]
              >
            • Patrick A. Timlin
              ... An LM317 only runs off DC. The efficiency of the LM317 is exactly the same regardless if you run it off a battery sourced DC or from an AC to DC conversion
              Message 6 of 25 , Nov 8, 2008
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                --- On Sat, 11/8/08, Steve <sungstad@...> wrote:
                > LM317 is OK if you are using AC power but inefficient
                > if you were running from batteries.

                An LM317 only runs off DC. The efficiency of the LM317 is exactly the same regardless if you run it off a battery sourced DC or from an AC to DC conversion source.

                If I recall correctly, the original poster was running the LM317 off a bench or plug in DC power supply and was using it to power the MP3 player INSTEAD of using batteries.


                > Simple switchers are not ideal for low voltage. For < 12V input you
                > should use a "synchronous" buck regulator to avoid diode losses.

                The LM317 is not a switcher. It is a linear regulator.

                And again, since the user is using a plug in 6V supply, the losses of a LM317 don't matter.

                Patrick Timlin
                http://www.geocities.com/ptimlin/
              • Shawn Upton
                The efficency is the same on batteries vs AC, but you missed the point: the LM317 wastes too much power (typically) to use when on batteries. The majority of
                Message 7 of 25 , Nov 8, 2008
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                  The efficency is the same on batteries vs AC, but you missed the point: the LM317 wastes too much power (typically) to use when on batteries. The majority of the batteries stored energy goes into heat. Ergo, one should use a switcher when on batteries for such a large difference in voltage.

                  Of course, at high power levels, it makes sense to use a switcher when on AC also--if only because of heatsinking issues. I believe Steve was indicating to go look for a "synchronous" switcher, he was not indicating that the LM317 is a SMPS in any way.
                  Shawn Upton, KB1CKT




                  ________________________________
                  From: Patrick A. Timlin <ptimlin@...>
                  To: Electronics_101@yahoogroups.com
                  Sent: Saturday, November 8, 2008 8:10:26 PM
                  Subject: Re: [Electronics_101] Re: 6v DC to 1.5v DC conversion


                  --- On Sat, 11/8/08, Steve <sungstad@yahoo. com> wrote:
                  > LM317 is OK if you are using AC power but inefficient
                  > if you were running from batteries.

                  An LM317 only runs off DC. The efficiency of the LM317 is exactly the same regardless if you run it off a battery sourced DC or from an AC to DC conversion source.

                  If I recall correctly, the original poster was running the LM317 off a bench or plug in DC power supply and was using it to power the MP3 player INSTEAD of using batteries.

                  > Simple switchers are not ideal for low voltage. For < 12V input you
                  > should use a "synchronous" buck regulator to avoid diode losses.

                  The LM317 is not a switcher. It is a linear regulator.

                  And again, since the user is using a plug in 6V supply, the losses of a LM317 don't matter.

                  Patrick Timlin
                  http://www.geocitie s.com/ptimlin/




                  [Non-text portions of this message have been removed]
                • Patrick A. Timlin
                  ... No, I didn t miss the point, because it is irrelevant to the discussion. The original poster is NOT using batteries. But to nitpick again, the LM317 wastes
                  Message 8 of 25 , Nov 8, 2008
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                    --- On Sat, 11/8/08, Shawn Upton <kb1ckt@...> wrote:
                    > but you missed the point: the LM317 wastes too much power
                    > (typically) to use when on batteries.

                    No, I didn't miss the point, because it is irrelevant to the discussion. The original poster is NOT using batteries.

                    But to nitpick again, the LM317 wastes the same power either way. I think you mean to imply the the amount of wasted energy is usually more of an issue with a battery supplied system. I mention it because I don't want newbies to read the above and come to the incorrect conclusion that an LM317 run off batteries is different that if run off another dc source.

                    Anyway, with a different MP3 player, the original poster's noise issue went away and he is happy. Just something about the other player allowed noise, likely it has no filtering at all since it was designed to run off a very quiet power source, a battery and the OP's supply might have been noisy which coupled through the LM317. The other player probably did a better design of the circuit and filtered out that noisy supply.

                    Patrick Timlin
                    http://www.geocities.com/ptimlin/
                  • Steve
                    ... discussion. The original poster is NOT using batteries. ... think you mean to imply the the amount of wasted energy is usually more of an issue with a
                    Message 9 of 25 , Nov 11, 2008
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                      --- In Electronics_101@yahoogroups.com, "Patrick A. Timlin"
                      <ptimlin@...> wrote:
                      >
                      > --- On Sat, 11/8/08, Shawn Upton <kb1ckt@...> wrote:
                      > > but you missed the point: the LM317 wastes too much power
                      > > (typically) to use when on batteries.
                      >
                      > No, I didn't miss the point, because it is irrelevant to the
                      discussion. The original poster is NOT using batteries.
                      >
                      > But to nitpick again, the LM317 wastes the same power either way. I
                      think you mean to imply the the amount of wasted energy is usually
                      more of an issue with a battery supplied system. I mention it because
                      I don't want newbies to read the above and come to the incorrect
                      conclusion that an LM317 run off batteries is different that if run
                      off another dc source.
                      >

                      Those are good reasons to point those things out (both of you).
                      Perhaps it was taken mistakenly as criticism of the poster, rather
                      than a clarification.

                      To clarify the point more, it isn't just that when on AC power there
                      is a lot more power available for next-to-nothing (relatively), it is
                      also that the losses in the AC to 6VDC power supply are almost
                      certainly -way- more than the power wasted in the LM317.

                      Someone mentioned being able to run an LM317 which is a TO-220 package
                      without a heatsink. In fact, I suspect he could use an LM317T which is
                      a TO-92 package rated at 100mA without issue. Simple enough to check
                      the current draw.

                      > Anyway, with a different MP3 player, the original poster's noise
                      issue went away and he is happy. Just something about the other player
                      allowed noise, likely it has no filtering at all since it was designed
                      to run off a very quiet power source, a battery and the OP's supply
                      might have been noisy which coupled through the LM317. The other
                      player probably did a better design of the circuit and filtered out
                      that noisy supply.
                      >

                      I suspect it might have been electronic ballast fluorescent noise and
                      that the first MP3 player was more susceptible as you suggest. I think
                      that all the Zip Drive power supplies I've seen are linear, not
                      switching supplies just due to the massive weight.

                      Steve Greenfield
                    • Steve
                      From newbies.txt: ....And please do NOT start a new thread by replying to another message. Even if you change the subject line completely and trim all the
                      Message 10 of 25 , Nov 11, 2008
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                        From newbies.txt:

                        ....And please do NOT start a new thread by replying to another
                        message. Even if you change the subject line completely and trim all
                        the original messages off, there is information in the hidden header
                        that Yahoogroups detects and then lists it as if it were part of that
                        thread.
                        To start a new thread, start a new message to the list address.
                        electronics_101@yahoogroups.com

                        Thanks,
                        Steve Greenfield
                        Your friendly neighborhood moderator

                        --- In Electronics_101@yahoogroups.com, Jim H <jimh@...> wrote:
                        >
                        > Hi Folks,
                        >
                        > I have a small amplifier project I¹ve been working on for a few
                        weeks now
                        > which uses a 6v DC supply. I¹m also using a 1.5v mp3 player to play the
                        > sound into the project. Is there a simple way to convert the 6v to
                        1.5v so
                        > that I can run everything from the one supply?
                        >
                        > Many Thanks
                        >
                        > Jim
                        >
                        >
                        > [Non-text portions of this message have been removed]
                        >
                      • Jim H
                        Thanks everyone for all your comments regarding the LM317 and power conversion. I¹ve really learned a lot using the LM317 and I especially like the
                        Message 11 of 25 , Nov 11, 2008
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                          Thanks everyone for all your comments regarding the LM317 and power
                          conversion. I¹ve really learned a lot using the LM317 and I especially like
                          the variability of the output (it means I can use it for other things in
                          future - electronics miser that I am!).

                          I did consider using the LM317T but checked the mp3 player consumption
                          beforehand which indicated a 150mA spike on startup so I opted for the more
                          robust version. It turns out that this was probably a good move because I
                          mixed up the pin outs at first and ended up frying a potentiometer!

                          My power source is indeed a heavy beast from an old Zip drive and therefore
                          almost certainly linear.

                          I¹m just glad that was lucky enough to have two different mp3 players to
                          test otherwise I¹d never have discovered that the noise was due to the
                          poorer filtering on the first player.

                          On a slightly different note I¹ve been continuing my tinkering with simple
                          amps (mostly Velleman kits or Kemo) and mp3 players. I¹ve noticed that some
                          of the amps I have seem to cause (or pick up) a lot more noise than others
                          and I had the idea of putting a ceramic capacitor between the output and
                          grnd. You¹ve probably guessed already that this caused even more noise. I
                          then tried a small electrolytic and this actually filtered out a lot of the
                          noise. What¹s happening when I do this?

                          Thanks again.

                          Jim



                          From: Steve <alienrelics@...>
                          Reply-To: <Electronics_101@yahoogroups.com>
                          Date: Tue, 11 Nov 2008 17:45:09 -0000
                          To: <Electronics_101@yahoogroups.com>
                          Subject: [Electronics_101] Re: 6v DC to 1.5v DC conversion


                          --- In Electronics_101@yahoogroups.com
                          <mailto:Electronics_101%40yahoogroups.com> , "Patrick A. Timlin"
                          <ptimlin@...> wrote:
                          >
                          > --- On Sat, 11/8/08, Shawn Upton <kb1ckt@...> wrote:
                          > > but you missed the point: the LM317 wastes too much power
                          > > (typically) to use when on batteries.
                          >
                          > No, I didn't miss the point, because it is irrelevant to the
                          discussion. The original poster is NOT using batteries.
                          >
                          > But to nitpick again, the LM317 wastes the same power either way. I
                          think you mean to imply the the amount of wasted energy is usually
                          more of an issue with a battery supplied system. I mention it because
                          I don't want newbies to read the above and come to the incorrect
                          conclusion that an LM317 run off batteries is different that if run
                          off another dc source.
                          >

                          Those are good reasons to point those things out (both of you).
                          Perhaps it was taken mistakenly as criticism of the poster, rather
                          than a clarification.

                          To clarify the point more, it isn't just that when on AC power there
                          is a lot more power available for next-to-nothing (relatively), it is
                          also that the losses in the AC to 6VDC power supply are almost
                          certainly -way- more than the power wasted in the LM317.

                          Someone mentioned being able to run an LM317 which is a TO-220 package
                          without a heatsink. In fact, I suspect he could use an LM317T which is
                          a TO-92 package rated at 100mA without issue. Simple enough to check
                          the current draw.

                          > Anyway, with a different MP3 player, the original poster's noise
                          issue went away and he is happy. Just something about the other player
                          allowed noise, likely it has no filtering at all since it was designed
                          to run off a very quiet power source, a battery and the OP's supply
                          might have been noisy which coupled through the LM317. The other
                          player probably did a better design of the circuit and filtered out
                          that noisy supply.
                          >

                          I suspect it might have been electronic ballast fluorescent noise and
                          that the first MP3 player was more susceptible as you suggest. I think
                          that all the Zip Drive power supplies I've seen are linear, not
                          switching supplies just due to the massive weight.

                          Steve Greenfield




                          [Non-text portions of this message have been removed]
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