Ground loop problem to my 802di fronts and HTM2di center

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  • Highroller
    Junior Member
    • Jan 2010
    • 27

    Ground loop problem to my 802di fronts and HTM2di center

    I have a hum in all three of my front speakers.

    The two fronts and center are connect to seperate MC501s connect to their own dedicated circuits.

    The MC501s are connected to an MX120.

    I have an MC207 connected 803S's in the back. The MC207 is connected to the MX120.

    I have three source systems connected to the MX120. A direct TV receiver, and Oppo 83 Nuforce and an MR88.

    The hum only comes of the fronts and center.

    The hum also only happens when going from 0 to 1 on the MX120 and then stays constant as I increase volume.

    I have disconnected the direct TV from the MX120.

    I would really appreciate any thoughts on how to best isolate this issue. Not sure where to go next.

    Many thanks
  • emig5m
    Senior Member
    • Aug 2008
    • 646

    #2
    I was going nuts trying to figure out a hum problem that only seemed to come out of some of the channels and it turned out to actually be the patch cables going from the pre/pro to the power amp. I replaced them with higher quality cables and the hum went away. I did verify the faulty cables by switching them to other channels. They where cheapy Monoprice cables so I just threw them out. The cables I replaced them with was Bluejeans... no more hum (actually it was more like a "buzz")

    Comment

    • stuofsci02
      Super Senior Member
      • Nov 2009
      • 1241

      #3
      Sounds like a groundloop issue. I believe it is because your MC501s are on a different circuit then the pre/pro. If the amps have a three prong plug they will be grounded to their circuit. Same thing with the Pre/Pro, but it will be grounded to a different circuit. Then once you connect them together with RCA or XLR they will be grounded to each other and the loop is born.

      You can test this theory by connecting your Pre/Pro to the same circuit as your 501s. This will likely cause a hum out of your rear speakers if the 207 was on the same circuit as the pre/pro.

      If this is the case it can be fixed...

      Cheers!
      Main System:
      B&W 801D
      Emotiva USP-1 Pre-Amp
      Chord SPM-650 Stereo Amp
      Oppo BDP-105
      Squeezebox Touch


      Second System:
      B&W CM7
      Emotiva UMC-1
      Emotiva UPA-2
      Oppo BDP-83SE
      Grant Fidelity DAC-09

      Comment

      • Highroller
        Junior Member
        • Jan 2010
        • 27

        #4
        Thanks. I will try that later this evening.

        fyi... each of the MC501 are on there own seperate circuit... 3 MC501s/3 separate circuits..

        so, I am not sure how to correct the problem if you theory proves out.

        I will try it later this evening and let you know.

        Many thanks

        Comment

        • Highroller
          Junior Member
          • Jan 2010
          • 27

          #5
          I tried connecting the pre amp to the same circuit as the MC501 circuit that powers the left front. the hum was still there in the left front.

          So, I am not sure where to head next..

          Thanks for the suggestion..

          Comment

          • bigburner
            Super Senior Member
            • May 2005
            • 2649

            #6
            Please confirm that your interconnects are separated from your power cables.

            Nigel.

            Comment

            • aarsoe
              Senior Member
              • May 2004
              • 795

              #7
              Start by turning everything on to be certain that the hum is still there. Then either mute or turn of the power amps and unplug one source and then un mute or turn your amps back on to see if the hum is still there. If it is then leave the source unplugged and repeat with the next source etc..
              If all sources can be removed without any reduction in hum then remove the back channel amplifiers. If there is still hum then disconnect the front amplifiers one at a time to see when then hum disappears.
              When you find the unit doing it the first try to change the cable you are using to see if it is defect. Alternatively if you based in Europe (your profile does not state where you are) see if you can turn the power plug 180 degrees to ensure that is not the issue. Normally that will not be an issue in the US.

              As a general word of advice I suggest buying a cable tester. Behringer makes a nice cheap one that can test RCA, XLR and jacks for headphones. Have too many cables that have been pulled from the pile with a bit more force that they where designed to deal with. Now if only they had a version with HDMI testing as well then that would really be something.. :-)

              Comment

              • jericho
                Senior Member
                • Dec 2004
                • 280

                #8
                Hello,

                I had the same problem in the beginning with my setup.I have 3 McIntosh 1201's, two 501's and two 252's.
                I had a lot of hum in my fronts and was told I had to disconnect the ground cable in the electricity plug.I did and everything was ok!!!Just give it a try

                Comment

                • style
                  Super Senior Member
                  • Feb 2006
                  • 1562

                  #9
                  @jericho,

                  yes is you go "cut" the ground from your power cord the hum will be no more present ..but 8O is not so good for your system.

                  I understand why the power souplly/ power conditioner are so used in Usa!!!


                  dont have the ground is a "risiko" for your gears!!

                  this is the last card to play. you muss try to reconnect all your units . a single unit or a cable make the ground noise in your front speakers. maybe without a player, a source (and reconnect it after) you can have a better solution.....


                  style

                  Comment

                  • Highroller
                    Junior Member
                    • Jan 2010
                    • 27

                    #10
                    Not sure I fully understand you question... but I will try to describe in more detail..

                    The three MC501s are connected to different 20 amp circuits in the wall. The MC501s are then connected to the 2 fronts and 1 center.

                    The MX120 is connected via blue jean balanced interconnects to each of the MC501s.

                    The MX120 is also connected to a MC207 powering the 803s in the back.

                    The 803s have no hum. The fronts and center have the hum.

                    Hope that answers you question

                    Comment

                    • Highroller
                      Junior Member
                      • Jan 2010
                      • 27

                      #11
                      Would it be okay to unplug the cables at the source rather than at the pre amp? It is much easier for me to do it this way but I want make sure that i have a valid test.

                      Also of note, the MC207 has a hum with the unit itself. I wonder if that would indicate it is the culprit?? I will certainly try it..

                      Is a ground loop just and irritation or does it hurt your system?

                      Comment

                      • jericho
                        Senior Member
                        • Dec 2004
                        • 280

                        #12
                        I'm using the amps without ground connection now for a few years, no hum, never had a problem. Don't use power conditioners with larger amps because you will use dynamics.

                        Just give it a try, only for a few minutes, and connect it again, you'll notice the difference


                        Regards

                        Jericho


                        By the way, we have 220-240 volt here in Belgium

                        style[/QUOTE]

                        Comment

                        • style
                          Super Senior Member
                          • Feb 2006
                          • 1562

                          #13
                          sorry jericho,

                          not see that you are in Belgium.
                          +100 for dynamic loss with power supplly....


                          when I had a Mc207 my left speaker have a hum too: with the "supressing" from the ground all work very fine like in your system.....

                          I understand your mean but the ground if is present is for a reason are present or?
                          (an electrician can give you technical answers ...)

                          you have a dedicat line ?

                          style

                          Comment

                          • Rod#S
                            Senior Member
                            • Oct 2010
                            • 474

                            #14
                            Originally posted by jericho
                            I'm using the amps without ground connection now for a few years, no hum, never had a problem. Don't use power conditioners with larger amps because you will use dynamics.

                            Just give it a try, only for a few minutes, and connect it again, you'll notice the difference


                            Regards

                            Jericho


                            By the way, we have 220-240 volt here in Belgium

                            style
                            [/QUOTE]


                            I find this depends on the power conditioner and shouldn't be said in such a way as to be a blanket statement. I use 3 relatively high output amps, 2 Bryston 4B-SSTs and a 6B-SST and all 3 are plugged into a Furman IT-Reference and I have never been able to notice a difference in performance when I have plugged them into the wall for comparison. The amps are all spec'd at beween 330-340 watts per channel. Before I had the 3 amps, just one 4B-SST I had that plugged into a power bar and indeed there was a noticeable effect on dynamics in that scenario when the amp was plugged into the wall. I noticed the same thing with my previous 5 channel Anthem MCA-50 amp. No noticeable difference between the wall and Furman but a definite difference between the power bar and wall.

                            Now having said that, would I notice a difference between the wall and Furman with say Bryston's 14B-SST stereo amp or their 7B-SST or 28B-SST mono blocks, possibly as those put out a lot more power, 600 watts per channel for the 14B-SST/7B-SST and 1000 watts for the 28B-SST. It would be an interesting experiment.

                            Rod
                            B&W 800 Diamonds (L/R), HTM2 Diamond (C), 802 Diamonds (SL/SR), Paradigm Signature Sub 25 (LFE), Reference Servo 15a x 2 (Stereo subs), Lexicon MC-12Bv5EQ SSP, Bryston 28B-SST2x 2, 7B-SST2x2, 4B-SST C Series, BDP-2, Oppo UDP-205, Pioneer Elite Kuro PRO-150FD, Furman SPR-20i, IT-Reference, Eastlink Maestro PVR, Xbox One & 360, PS3, Siltech Golden Ridge II, Ruby Hill IIx2, 330ix2, Kimber Kable PK10 Gold, Tonic, PBJ, Cadence, HD19e, HD19, OPT-1, HDSW 4x1, Ixos 6003, Harmony 1000

                            Comment

                            • jericho
                              Senior Member
                              • Dec 2004
                              • 280

                              #15

                              I find this depends on the power conditioner and shouldn't be said in such a way as to be a blanket statement. I use 3 relatively high output amps, 2 Bryston 4B-SSTs and a 6B-SST and all 3 are plugged into a Furman IT-Reference and I have never been able to notice a difference in performance when I have plugged them into the wall for comparison. The amps are all spec'd at beween 330-340 watts per channel. Before I had the 3 amps, just one 4B-SST I had that plugged into a power bar and indeed there was a noticeable effect on dynamics in that scenario when the amp was plugged into the wall. I noticed the same thing with my previous 5 channel Anthem MCA-50 amp. No noticeable difference between the wall and Furman but a definite difference between the power bar and wall.

                              Now having said that, would I notice a difference between the wall and Furman with say Bryston's 14B-SST stereo amp or their 7B-SST or 28B-SST mono blocks, possibly as those put out a lot more power, 600 watts per channel for the 14B-SST/7B-SST and 1000 watts for the 28B-SST. It would be an interesting experiment.

                              Rod[/QUOTE]
                              I didn't mean you have to take it as a blank statement my expression about those conditioners, but in my case, using McIntosh 1.2Kw amps and 501 amps, I can tell you there is a lot of loss in dynamics

                              Regards

                              Jericho

                              Comment

                              • Rod#S
                                Senior Member
                                • Oct 2010
                                • 474

                                #16
                                Wow, so you are running 2 1.2Kw amps and what, 3 or 5 501 amps? Man that is some serious power. Do you have dedicated circuits? Your speakers must truly sign with that kind of juice. Is that a picture of your front end in your avatar, 800D and HTM1D? What are you using for surrounds, subs (they look like B&W) and SSP?

                                Rod
                                B&W 800 Diamonds (L/R), HTM2 Diamond (C), 802 Diamonds (SL/SR), Paradigm Signature Sub 25 (LFE), Reference Servo 15a x 2 (Stereo subs), Lexicon MC-12Bv5EQ SSP, Bryston 28B-SST2x 2, 7B-SST2x2, 4B-SST C Series, BDP-2, Oppo UDP-205, Pioneer Elite Kuro PRO-150FD, Furman SPR-20i, IT-Reference, Eastlink Maestro PVR, Xbox One & 360, PS3, Siltech Golden Ridge II, Ruby Hill IIx2, 330ix2, Kimber Kable PK10 Gold, Tonic, PBJ, Cadence, HD19e, HD19, OPT-1, HDSW 4x1, Ixos 6003, Harmony 1000

                                Comment

                                • jericho
                                  Senior Member
                                  • Dec 2004
                                  • 280

                                  #17
                                  Originally posted by Rod#S
                                  Wow, so you are running 2 1.2Kw amps and what, 3 or 5 501 amps? Man that is some serious power. Do you have dedicated circuits? Your speakers must truly sign with that kind of juice. Is that a picture of your front end in your avatar, 800D and HTM1D? What are you using for surrounds, subs (they look like B&W) and SSP?

                                  Rod

                                  The system is more or less like the avator but there is al lot more :

                                  2x 1.2 Kw McIntosh on 800D as front
                                  1x 1.2 Kw McIntosh on center HTM-1D
                                  2x 501 McIntosh on surrounds 802D
                                  2x 252 McIntosh in bridged mode on back surrounds 803D
                                  2x sub ASW855
                                  1x sub ASW825
                                  2x sub DB1 (will arrive next month)

                                  Processor MX150 McIntosh
                                  Blu ray McIntosh MVP881
                                  DVD McIntosh MVP871
                                  MCD/MDA 1000 combo McIntosh
                                  MS300 & MS750 Music Server McIntosh
                                  Wadia 171i
                                  Sonos system

                                  Comment

                                  • Rod#S
                                    Senior Member
                                    • Oct 2010
                                    • 474

                                    #18
                                    Originally posted by jericho
                                    The system is more or less like the avator but there is al lot more :

                                    2x 1.2 Kw McIntosh on 800D as front
                                    1x 1.2 Kw McIntosh on center HTM-1D
                                    2x 501 McIntosh on surrounds 802D
                                    2x 252 McIntosh in bridged mode on back surrounds 803D
                                    2x sub ASW855
                                    1x sub ASW825
                                    2x sub DB1 (will arrive next month)

                                    Processor MX150 McIntosh
                                    Blu ray McIntosh MVP881
                                    DVD McIntosh MVP871
                                    MCD/MDA 1000 combo McIntosh
                                    MS300 & MS750 Music Server McIntosh
                                    Wadia 171i
                                    Sonos system

                                    8O ;x( OMG! That is one SERIOUS setup. Are you adding 2 DB1's for a total of 5 subs or are the DB1's replacing the 2 ASW855's?
                                    B&W 800 Diamonds (L/R), HTM2 Diamond (C), 802 Diamonds (SL/SR), Paradigm Signature Sub 25 (LFE), Reference Servo 15a x 2 (Stereo subs), Lexicon MC-12Bv5EQ SSP, Bryston 28B-SST2x 2, 7B-SST2x2, 4B-SST C Series, BDP-2, Oppo UDP-205, Pioneer Elite Kuro PRO-150FD, Furman SPR-20i, IT-Reference, Eastlink Maestro PVR, Xbox One & 360, PS3, Siltech Golden Ridge II, Ruby Hill IIx2, 330ix2, Kimber Kable PK10 Gold, Tonic, PBJ, Cadence, HD19e, HD19, OPT-1, HDSW 4x1, Ixos 6003, Harmony 1000

                                    Comment

                                    • wettou
                                      Ultra Senior Member
                                      • May 2006
                                      • 3389

                                      #19
                                      Originally posted by jericho
                                      The system is more or less like the avator but there is al lot more :

                                      2x 1.2 Kw McIntosh on 800D as front
                                      1x 1.2 Kw McIntosh on center HTM-1D
                                      2x 501 McIntosh on surrounds 802D
                                      2x 252 McIntosh in bridged mode on back surrounds 803D
                                      2x sub ASW855
                                      1x sub ASW825
                                      2x sub DB1 (will arrive next month)

                                      Processor MX150 McIntosh
                                      Blu ray McIntosh MVP881
                                      DVD McIntosh MVP871
                                      MCD/MDA 1000 combo McIntosh
                                      MS300 & MS750 Music Server McIntosh
                                      Wadia 171i
                                      Sonos system
                                      Sweet :B Pictures please
                                      Farming looks mighty easy when your plow is a pencil, and you're a thousand miles from the corn field."Dwight D. Eisenhower

                                      Comment

                                      • dukester
                                        Senior Member
                                        • Sep 2010
                                        • 198

                                        #20
                                        Originally posted by jericho
                                        The system is more or less like the avator but there is al lot more :

                                        2x 1.2 Kw McIntosh on 800D as front
                                        1x 1.2 Kw McIntosh on center HTM-1D
                                        2x 501 McIntosh on surrounds 802D
                                        2x 252 McIntosh in bridged mode on back surrounds 803D
                                        2x sub ASW855
                                        1x sub ASW825
                                        2x sub DB1 (will arrive next month)

                                        Processor MX150 McIntosh
                                        Blu ray McIntosh MVP881
                                        DVD McIntosh MVP871
                                        MCD/MDA 1000 combo McIntosh
                                        MS300 & MS750 Music Server McIntosh
                                        Wadia 171i
                                        Sonos system
                                        Wicked set-up...amazing that you disconnected the gnd wire. Not because i'm an electical expert but bec i've always been told to never do that. Someone in this forum has got to be an expert on this topic and will hopefully chime in.

                                        Off topic
                                        Jericho: I have a 171i on order...w/c DAC are you using? How is your 171i connected, and how is the sound quality through your 800D's?
                                        Last edited by dukester; 11 March 2011, 18:58 Friday.
                                        McIntosh C2300/MC302, NAD T785, Oppo 83se & 105, Squeezebox Touch, AppleTV, B&W 803Di/HTM2Di/M1, REL G1, Sony XBR9, PS3

                                        Comment

                                        • scanido
                                          Senior Member
                                          • Apr 2006
                                          • 548

                                          #21
                                          Originally posted by jericho
                                          The system is more or less like the avator but there is al lot more :

                                          2x 1.2 Kw McIntosh on 800D as front
                                          1x 1.2 Kw McIntosh on center HTM-1D
                                          2x 501 McIntosh on surrounds 802D
                                          2x 252 McIntosh in bridged mode on back surrounds 803D
                                          2x sub ASW855
                                          1x sub ASW825
                                          2x sub DB1 (will arrive next month)

                                          Processor MX150 McIntosh
                                          Blu ray McIntosh MVP881
                                          DVD McIntosh MVP871
                                          MCD/MDA 1000 combo McIntosh
                                          MS300 & MS750 Music Server McIntosh
                                          Wadia 171i
                                          Sonos system
                                          unbelievable awesome setup!!

                                          Comment

                                          • jericho
                                            Senior Member
                                            • Dec 2004
                                            • 280

                                            #22
                                            Originally posted by dukester
                                            Wicked set-up...amazing that you disconnected the gnd wire. Not because i'm an electical expert but bec i've always been told to never do that. Someone in this forum has got to be an expert on this topic and will hopefully chime in.

                                            Off topic
                                            Jericho: I have a 171i on order...w/c DAC are you using? How is your 171i connected, and how is the sound quality through your 800D's?

                                            It's connected with a digital Wireworld cable to the MDA1000 Dac.Using the iphone or the ipod with ALAC files it give's a pretty result, I can not hear the difference with the original cd.

                                            Comment

                                            • Rod#S
                                              Senior Member
                                              • Oct 2010
                                              • 474

                                              #23
                                              Originally posted by wettou
                                              Sweet :B Pictures please
                                              I second this motion! :B
                                              B&W 800 Diamonds (L/R), HTM2 Diamond (C), 802 Diamonds (SL/SR), Paradigm Signature Sub 25 (LFE), Reference Servo 15a x 2 (Stereo subs), Lexicon MC-12Bv5EQ SSP, Bryston 28B-SST2x 2, 7B-SST2x2, 4B-SST C Series, BDP-2, Oppo UDP-205, Pioneer Elite Kuro PRO-150FD, Furman SPR-20i, IT-Reference, Eastlink Maestro PVR, Xbox One & 360, PS3, Siltech Golden Ridge II, Ruby Hill IIx2, 330ix2, Kimber Kable PK10 Gold, Tonic, PBJ, Cadence, HD19e, HD19, OPT-1, HDSW 4x1, Ixos 6003, Harmony 1000

                                              Comment

                                              • wettou
                                                Ultra Senior Member
                                                • May 2006
                                                • 3389

                                                #24
                                                The best way to resolve ground loop issues is to have a dedicated line and poof the ground loop issues go away :T :B
                                                Farming looks mighty easy when your plow is a pencil, and you're a thousand miles from the corn field."Dwight D. Eisenhower

                                                Comment

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