Question about 12V ripple

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  • Pentium4
    CapXon Be Gone
    • Sep 2011
    • 3741
    • USA

    #1

    Question about 12V ripple

    Worried ripple might be too high on this system I'm using daily. It's my Xigmatek PSU https://www.badcaps.net/forum/showpo...postcount=1156

    I think it's good for 350W at least but I'm worried about the 12V ripple. All it has on the 12V is 1 pi coil and one 4700uF Panny FR cap. It's powering a Core 2 Duo 2.4GHz proc, 4GB RAM with a BFG GTX 260 and a single SSD drive. Sometimes when doing medium gaming, the PSU gets around 200W. Efficiency is around 77% I don't have an oscilloscope but as a guess would you say the ripple isn't that bad?
    Last edited by Pentium4; 03-25-2013, 12:01 AM.
  • Wester547
    -
    • Nov 2011
    • 1268
    • USA.

    #2
    Re: Question about 12V ripple

    Though I would recommend at least two filtering capacitors for each output, 4700uF x1 should be theoretically enough for the +12V rail... so long as the ripple is well under 120mV (that's quite a bit of electrical noise and heat), you should be okay. Any PSU that gives off 100mV of ripple on the +12V rail isn't one that I'd feel safe with, though. I would guess that the heat output from the PSU itself isn't bad, overall? If you don't feel safe with it right now, I don't think it would hurt to add an extra 2200uF capacitor on the +12V output (if there's room). Note that 120mV is the limit for the +12V rail and 50mV the specified limit for the +3.3V and +5V rails.

    Comment

    • Pentium4
      CapXon Be Gone
      • Sep 2011
      • 3741
      • USA

      #3
      Re: Question about 12V ripple

      Yeah I wish there was another slot for a cap but there wasn't, that's why I put a huge 16V cap in the only spot I figured the coil would help some too though, even at 200W it doesn't kick out a ton of heat because my room is around around 15C

      Comment

      • ben7
        Capaholic
        • Jan 2011
        • 4059
        • USA

        #4
        Re: Question about 12V ripple

        Just a note - adding/decreasing capacitance and/or esr can cause MORE ripple in some psus!
        Muh-soggy-knee

        Comment

        • Wester547
          -
          • Nov 2011
          • 1268
          • USA.

          #5
          Re: Question about 12V ripple

          ^ I would guess that augmenting capacitance can increase ripple because as capacitance goes up in capacitors, ESR goes lower (larger can sizes, usually, so higher ripple current and lower ESR rating...).
          Last edited by Wester547; 03-26-2013, 06:07 PM.

          Comment

          • c_hegge
            Badcaps Legend
            • Sep 2009
            • 5219
            • Australia

            #6
            Re: Question about 12V ripple

            I have load tested a similar PSU (http://www.hardwareinsights.com/wp/a...520c-review/2/). The ripple was a little high, but still in spec.
            I love putting bad caps and flat batteries in fire and watching them explode!!

            No wonder it doesn't work! You installed the jumper wires backwards

            Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium

            Office PC: HP ProLiant ML150 G3, 2x Xeon E5335 2GHz, 4GB DDR2 RAM, 120GB Intel 530 SSD, 2x 250GB HDD, 2x 450GB 15K SAS HDD in RAID 1, 1x 2TB HDD, nVidia 8400GS, Delta DPS-650BB 650W PSU, Windows 7 Pro

            Comment

            • ben7
              Capaholic
              • Jan 2011
              • 4059
              • USA

              #7
              Re: Question about 12V ripple

              Originally posted by Wester547
              ^ I would guess that augmenting capacitance can increase ripple because as capacitance goes up in capacitors ESR goes lower (larger can sizes, usually, so higher ripple current and lower ESR rating...).
              It affects the way the control loop works, and the frequencies that get filtered out.
              Muh-soggy-knee

              Comment

              • Pentium4
                CapXon Be Gone
                • Sep 2011
                • 3741
                • USA

                #8
                Re: Question about 12V ripple

                Shoot....I hope the ripple isn't higher! I used my little ESR meter and the Panny cap was actually 0.01 higher than the Teapo if I remember correctly

                Comment

                • c_hegge
                  Badcaps Legend
                  • Sep 2009
                  • 5219
                  • Australia

                  #9
                  Re: Question about 12V ripple

                  ^
                  a 0.01 ohm difference isn't going to make much difference.
                  I love putting bad caps and flat batteries in fire and watching them explode!!

                  No wonder it doesn't work! You installed the jumper wires backwards

                  Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium

                  Office PC: HP ProLiant ML150 G3, 2x Xeon E5335 2GHz, 4GB DDR2 RAM, 120GB Intel 530 SSD, 2x 250GB HDD, 2x 450GB 15K SAS HDD in RAID 1, 1x 2TB HDD, nVidia 8400GS, Delta DPS-650BB 650W PSU, Windows 7 Pro

                  Comment

                  • momaka
                    master hoarder
                    • May 2008
                    • 12175
                    • Bulgaria

                    #10
                    Re: Question about 12V ripple

                    Originally posted by ben7
                    Just a note - adding/decreasing capacitance and/or esr can cause MORE ripple in some psus!
                    Only somewhat true.

                    Increasing the capacitance alone without lowering the ESR or increasing the ripple current will actually decrease the output noise and ripple. However, Wester547 stated a valid point - the can size of the capacitor often becomes larger with increasing capacitance, so that means the ESR is lowered and the ripple current increased - and this is exactly what can cause the PSU to actually output more noise.

                    The 4700uF Panasonic FR should be fine, though - of course, all depending on the TDP rating of the Core 2 Duo and the 260 GTX. I've successfully ran a 107 W TDP CPU with a Macron MPT-301 PSU that has only a single 3300uF 16V Chemicon KZE cap for the 12V rail.

                    Comment

                    • Wester547
                      -
                      • Nov 2011
                      • 1268
                      • USA.

                      #11
                      Re: Question about 12V ripple

                      EDIT: Nevermind, his PSU is a half bridge too...

                      Comment

                      • Pentium4
                        CapXon Be Gone
                        • Sep 2011
                        • 3741
                        • USA

                        #12
                        Re: Question about 12V ripple

                        Originally posted by momaka
                        Only somewhat true.

                        Increasing the capacitance alone without lowering the ESR or increasing the ripple current will actually decrease the output noise and ripple. However, Wester547 stated a valid point - the can size of the capacitor often becomes larger with increasing capacitance, so that means the ESR is lowered and the ripple current increased - and this is exactly what can cause the PSU to actually output more noise.

                        The 4700uF Panasonic FR should be fine, though - of course, all depending on the TDP rating of the Core 2 Duo and the 260 GTX. I've successfully ran a 107 W TDP CPU with a Macron MPT-301 PSU that has only a single 3300uF 16V Chemicon KZE cap for the 12V rail.
                        Cool They're both running at stock speeds and the case has good airflow. And at least it has an SSD instead of a spinning disk, so slightly less 12V needed

                        Comment

                        • Wester547
                          -
                          • Nov 2011
                          • 1268
                          • USA.

                          #13
                          Re: Question about 12V ripple

                          Originally posted by momaka
                          the can size of the capacitor often becomes larger with increasing capacitance, so that means the ESR is lowered and the ripple current increased - and this is exactly what can cause the PSU to actually output more noise.
                          I was of the impression that there wasn't such a thing as "too high a ripple current" in capacitors... if only because it increases the maximum amount of ripple they can handle (the maximum permissible ripple current for the capacitors, though I know that lower ESR ratings and higher ripple current ratings in capacitors are almost unavoidably synonymous with larger can sizes), but then a good design will be such that there won't be much ripple to begin with.

                          However, in saying that, if capacitors allow more ripple into the PSU (and thereby out) since they can handle it with a higher ripple current, it does make sense... unless you mean that the higher the ripple current, the more ripple has to be "released" to ground.
                          Last edited by Wester547; 04-05-2013, 03:26 AM.

                          Comment

                          • ben7
                            Capaholic
                            • Jan 2011
                            • 4059
                            • USA

                            #14
                            Re: Question about 12V ripple

                            I think it is more the different esr and/or capacitance messes with the pole in the feedback loop. Unique sure could tell us.
                            Muh-soggy-knee

                            Comment

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