8 Replies Latest reply on Oct 20, 2017 4:37 AM by brgeo

    NUC buzzing if separated from power line

    brgeo

      Hello,

      I have a NUC6CAYH. Everything works fine: connected to a ASUS Monitor by HDMI/DVI, usb wireless mouse and keyboard and to loudspeakers by 3.5 plug/cinch.

      If I turn off the NUC and disconnect the power line I get an extremly loud buzzing from the loudspeakers. I cannot avoid this although I tried a noise filter betweeen the NUC and the loud speakers.

      If I keep the power line connected everything is quite.

      Does anybody have an idea for a workaround? Is it a failure of the NUC? In general or just mine?

      I have so many pc's without any problem of this kind.

      Best regards

      Gerhard

        • 1. Re: NUC buzzing if separated from power line
          Intel Corporation
          This message was posted on behalf of Intel Corporation

          Hello brgeo,
           
          I understand there is a buzzing sound coming from the speakers when you disconnect power cord from the Intel® NUC Kit NUC6CAYH.
           
          Let me apologize for any inconvenience this issue may be causing to you.
           
          There is a chance there might be some charge still on the computer when you remove the power cord.  If possible after disconnecting the power cord press and hold the power button down on the computer for 10-15 seconds and check if the buzzing sound goes away.  This is just to make sure there is no charge left in the computer after you remove the power cord.
           
          If possible try different 3.5mm cable and/or different speakers.
           
          Let me know if issue persists or not.
           
          Regards,
          Fred D.

          • 2. Re: NUC buzzing if separated from power line
            MNBadger

            Hi brgeo,

               I am reasonably sure that the buzzing you heard is 60 (or 50) Hz pickup from building power lines. It is not an NUC or a connector issue. When the NUC power cord is connected, a system ground is provided which shuts the AC noise to building ground. When disconnected, the cables to your speakers and their amplifier act as an antenna which picks up the room AC noise and amplifies it sending it to the speaker. There are several things one can do but some are easier than others. One way would be to turn off power to the speaker/amplifiers. In my setup I use a Smart Power switch that senses when the NUC is powered off and removes power to my speaker amplifiers and subwoofer. I suppose you could also try a ground wire from your NUC chassis to the building ground (like the safety prong of the AC plug). There are other ways but they sometimes get to be more involved.

             

            Hope this helps.

            Regards,

            MNBadger

            1 of 1 people found this helpful
            • 3. Re: NUC buzzing if separated from power line
              brgeo

              Hello Fred,

              many thanks for your response.

              I tried the charge issue - without any change.

              Although I tried to use other plugs and cables - no change.

              If I unplug everything from NUC (HDMI, keyborad, mouse, power supply) and leave the speakers connected only: I get the noise.

               

              My speakers are BOSE Companion 2 (3.5 plug - cinch connection). But I can reproduce the same problem with a HAMA DIR 3100 where I use the Aux In (3.5 plug-3.5 plug connection.

               

              I can use a Laptop with power supply and without and use the speakers - no problem.

              It is clear for me that it is ground loop (dt. "Masseschleife") problem that is due to NUC.

               

              My actual solution is to switch the speakers off with the NUC. This works, but during turn off and on phases there are situations where the speakers still produce loud (short) noise.

              As I want to use the speakers for a second device, it is not the optimal solution.

              May be you have further ideas.

              Many thanks and best regrads

              Gerhard

              • 4. Re: NUC buzzing if separated from power line
                brgeo

                Hello MNBadger,

                many thanks for your ideas. I tried several things during weekend. Please see also my response to INTEL (Fred).

                I actually turn the speakers off as you suggested, but it is not satisfying.

                I would like to try the ground wire connection you mentioned. I would use a power supply plug and connect a cable to "ground", but where can I connect it at NUC?

                Many thanks and best regards

                Gerhard

                • 5. Re: NUC buzzing if separated from power line
                  Intel Corporation
                  This message was posted on behalf of Intel Corporation

                  Hello brgeo,
                   
                  I am sorry to hear you are still having issues with your computer.
                   
                  What I can recommend is checking for grounding issues as MNBadger said.
                   
                  I found an article online which might help https://itstillworks.com/there-humming-speakers-7735.html
                   
                  The content on the above site is not controlled by Intel. This information is offered for your convenience and should not be viewed as an endorsement by Intel for the merchants or services offered there.
                   
                  Regards,
                  Fred D.

                  • 6. Re: NUC buzzing if separated from power line
                    MNBadger

                    Hi Gerhard,

                        I prefer not to have to open up my NUC to bring out a ground wire and I assume you would also like to avoid it. One way to access the NUC system ground is to find a DC power plug that matches that used on your NUC power connector (where the power supply plugs into the NUC). The outside barrel is the system ground. Therefore you could make a single wire cable that just brings the system ground from the barrel over to the house ground. Use caution!

                     

                    The DC power connector can be obtained from EBAY or an electronics part supplier. I use EBAY for best prices but make sure you buy the right size by taking some measurements from the power supply DC connector (AC side unplugged).

                     

                    I also had another thought while typing this. It could be that the speaker and it's amplifier has a separate power supply that has a floating output. See if you can reverse the AC plug assuming it is a non-polarized plug and not a three prong or polarized plug. Check for noise with that small change if possible.

                     

                    Good luck

                    MNBadger

                    • 7. Re: NUC buzzing if separated from power line
                      Intel Corporation
                      This message was posted on behalf of Intel Corporation

                      Hello brgeo and MNBadger,
                       
                      My best recommendation would be checking first with an electrician where the issue is.  An electrician should be able to find where the ground loop is.
                       
                      Regards,
                      Fred D.

                      • 8. Re: NUC buzzing if separated from power line
                        brgeo

                        Hallo Fred and all,

                        sorry for the late answer, but I was abroad.

                        I meanwhile saved the problem by using the toslink adapter of my NUC.

                        (Comment for other users: Please be aware that it is always written in the specifications and data sheets that there is a "Toslink" connection at the NUC - the truth is: it is a mini toslink 3.5 mm and in most cases you need an additional adapter: https://www.amazon.de/gp/product/B000LB65XO/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1)

                        I tried many things also with the help of an electrician. It is definitivly a problem of NUC as it makes the power loop, when being disconnected from the power supply.

                        If there is any further improvement by INTEL I would be happy to be informed as I like the NUC but will actually not buy anotherone for my living room.

                        Best regard

                        Gerhard