Grounding issue (I think)

Discussion in 'AV System Setup and Support' started by Michael Scott, May 16, 2019.

  1. Michael Scott

    Michael Scott Moderator / Reviewer
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    Ok guys, I have what I think is a ground loop issue of some sort. What's happening is that I'm getting a buzz in my speakers (not my subs from what I can tell). This system has 5 SEOS high sensitivity drivers in them so I assumed at first it was just ground floor noise that they were picking up as you couldn't hear the buzz unless you were on top of the speakers. Now the buzz has intensified to where I can hear it at quiet points in a movie (meaning it's gotten louder). it's not a hum, not a crackle, but a distinct "buzz" that rises and lowers it's volume depending on the volume of the receiver

    I've been troubleshooting the last 24 hours like a madman and THOUGHT I had it fixed, but now I'm not sure what is the actual cause as several things seem to get rid of it.

    First I thought it was my Peavey IPR amp for my passive subs as that can be a typical issue. Well, unplug the sub (or any link from the sub to the receiver, such as disconnecting the mini-dsp in between, pulling the rca cable connecting the minidsp to the amp, or pulling the sup cables from the xlr ports on the back). I found that bypassing the minidsp didn't change anything, as plugging the xlr to rca cables from the amp directly into the receiver introduced the speaker buzz again. I change the plug over to another circuit in the house and it fixes the hum. HOWEVER, that circuit of the house is older and doesn't having a grounding plug, so I'm not wild about there. Plugging the peavey amp into another outlet on the circuit doesn't change it either.

    now here's the kicker. I thought I had found it with the amp, but when I turned off my Blu-ray player.... BOOOOM. Instantly the buzz went away. getting puzzled I looked into it. Even with the sub plugged in and going, if I disconnected the Blu-ray player from the receiver (from the HDMI cord, or just powering it down and off) the buzz would go away. At first I thought I just had a crummily shielded HDMI cable or power cable so I swapped out the HDMI cable and plugged the player into another outlet. still the same thing. Then I started playing around. The buzz goes away IF I change the HDMI input on the receiver (say I have the player plugged into HDMI input 2. if I change to HDMI Input 3 on the receiver, and the player and sub are still going, the buzz vanishes. same with 1, 4 and 5, but If I got back to the active HDMI 2 with the Blu-ray player on and the peavey plugged in, then the buzz starts up again. muting knocks the buzz off, as does lowering the volume to zero.

    Thinking I had a bad port I started moving the player over to other HDMI inputs (1, 3, 4 and 5) and the buzz follows once you change the receiver over to those inputs. Then I tried something else. I pulled my Redmere HDMI cable from the back of the receiver and BOOM... instantly went away. plugged it into my BR player and of course it had no buzzes (the hdmi from the player to the receiver was unplugged so of course it didn't). my BR player doesn't have dual HDMI outputs otherwise I'd check to plug the projector cable into the player and run a separate out to the receiver for audio to see if that fixes it, but no dice there.

    Now I'm scratching my head. if only one thing affected the buzz then it would be easy to nail down. A faulty ground loop with the sub amp and call it a day. But it's the other 3 things affecting the buzz when amp is plugged in that makes me wonder if there's more to it. Unplugging the projector's redmere cable does the trick, unplugging the amp (or it's connection from the amp to the receiver) does the trick, unplugging the Blu-ray player does the trick (the hdmi or powering down, as if it's powered up AND connected with the HDMI cable to the receiver then it insantly starts static) etc. With multiple things affecting it I'm literally at my wits end trying to figure out WHAT is the cause!

    1. Is it my sub amp?
    2. Is it the redmere active HDMI cable going bad and causing interference?
    3. Multiple players were tested and all exhibit the same thing when turned on and connected to the receiver
    4. Is it my Yamaha receiver going belly up? (either ports or the internals)
    5 other options that my crazy mind can't think up.

    at this point I could start switching out half the components in my room trying to nail it down so I've gotten more and more confused as troubleshooting only shows MORE options it could be instead of isolating

    I tested my grounding in the outlets (older house from the 80s) and I got 125 volts when testing in the hot/neutral slots and when moving the neutral to the grounding "third plug" and/or the grounding screw in the center of the outlet. all outlets on the circuit show the same voltage so I'm pretty sure I don't have a bad ground on the house end
     
    #1 Michael Scott, May 16, 2019
    Last edited: May 16, 2019
  2. Sonnie

    Sonnie Senior Admin
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    Do you have a 75 ohm cable coming in to your system for cable or satellite?
     
  3. Michael Scott

    Michael Scott Moderator / Reviewer
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  4. Sonnie

    Sonnie Senior Admin
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    That may be a tough one.

    Have you tried taking a short wire and grounding the chassis of the player to the receiver (antenna connection if you have one)?
     
  5. Michael Scott

    Michael Scott Moderator / Reviewer
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    Haven't tried that yet, but I will later today when I give it a run

    What's weird is after about a billion hours of testing the buzz vanished last night and didn't come back till I powered down the system.

    At the moment I'm leaning towards bad receiver, bad power strip (it's older than I wanted so it might not be getting proper draw) or bad power amp. My electrician buddy thought I might have had a bad ground and it was my homes fault but testing each outlet showed a good ground
     
  6. ddude003

    ddude003 Senior Member

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    My guess is that Redmere is magnifying an issue somewhere... Google is your frenemy, search for Redmere issues and see if anything sounds familiar...
     
  7. Michael Scott

    Michael Scott Moderator / Reviewer
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    that's one thing I've wondered. Active cables WILL go bad over time as they degrade, and this cable is just over 5 years old . I only got it back in the day cuz it was a way to get a 50 ft cable run without needing an extender or using extra thick cables

    I've been nervous about trying a passive cable as any GOOOD passive cable at the 50 ft range is some nasty bucks.

    do the newer active cables at monoprice like the luxe or cabernet cables have the same issues that redmere had? I'm only doing 1080p from a JVC RS46 for the time being so I don't need to get full 4K with HDR on this particular setup. Also, if running passive. I know 50 ft is pushing it for a passive run, but will the 10.2 gbps passive cables from mono be enough? . I can't remember the last time I ran a passive run from my projector as I got my first redmere in 2012, and the one I'm using now in 2014 so I can't remember if I ever needed a length that long. I remember back i the day 50 foot was kind of "oohhh, I might rethink that" for 1080p, but not sure how advances in tech and bandwidth have affected that mantra
     
    #7 Michael Scott, May 16, 2019
    Last edited: May 16, 2019
  8. Negatron

    Negatron Moderator
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    Just a thought... have you tried flipping the power cord (positive to negative) on the bluray? I am assuming it is a 2 prong plug and not a 3 prong.
     
  9. Michael Scott

    Michael Scott Moderator / Reviewer
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    not yet. didn't think of that. And yes it's a 2 pronger, not a 3 prong.
     
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  10. Negatron

    Negatron Moderator
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    I recently read an article where they said they found the amp plug wired wrong straight from the factory.
     
  11. Michael Scott

    Michael Scott Moderator / Reviewer
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    and just checked. nothing. also, taking the player OFF the circuit entirely and putting it on another circuit via extension cord doesn't do anything either. Same with a grounding wire from the receiver to the amp or the player


    only things that seem to get rid of it are

    1. Flukes (last night it vanished after about 3 hours of plugging and unplugging things).
    2. Unplug the sub amps from the receiver somehow
    3. Plug the sub amp in on another circuit in the house
    4 unplug the Redmere HDMI cable from the receiver
    5. Turn off the player
    6. unplug the hdmi cord from the player to the receiver.

    as for the plug, that's a POSSIBILITY, but I've been running this same amp for over 6 years and it was used by someone on AVS for a few years before that with no problems for either of us. I'd guess failure before the plug being wired wrong
     
  12. Negatron

    Negatron Moderator
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    The only other thing I could think of would be florescent lights, or LED dimmers...
     
  13. Michael Scott

    Michael Scott Moderator / Reviewer
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    and lo and behold I FOUND IT. It was a surge protector for my projector. instead of wiring a 50 foot power cable down the wall, I used a 20 foot one and wired it into the back of the room (which is on a separate circuit than the front of the room where my rack is). Well, come to find out that it's the same outlet that my spare living room tv is on. I suddenly got the bright idea to just start unplugging things on that side of the room and as soon as I unplugged the TV and PS3 from the power strip the feedback buzz went down DRAMATICALLY (leaving only the projector on that power strip in the back room circuit). realizing that the interference from the other AV equipment was creating a bridge to the other circuit THROUGH the HDMI cable, I unplugged the projector and got an extension cord and wired it to the front of the room on the same circuit as the other AV equipment. suddenly it vanished completely.

    I think the surge protector was failing too (it was 5 years old) as I heard a light buzzing from it when the ps3 and TV were plugged into it. I'm guessing it was allowing some noise to bleed into the other plugs and followed up the projector cord into the other circuit. well. time to buy a few more Tripp Lite surge protectors to make sure it doesn't happen to my others, and go back to watching without that irritating speaker buzz coming through
     
    #13 Michael Scott, May 17, 2019
    Last edited: May 18, 2019 at 9:38 PM
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  14. Negatron

    Negatron Moderator
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    That is great news!
     
  15. Michael Scott

    Michael Scott Moderator / Reviewer
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    lol that it is. It was never a bad buzz, just enough to be heard when loading the disc at menu when there was no noise. But my OCD was driving me CRAZY trying to nail this down.
     
  16. Negatron

    Negatron Moderator
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    I have a similar problem, but I know mine is coming from one of my Insteon scene controllers when I turn on one light...if I turn it on with the normal Insteon switch it has no noise. I will get it figured out before I finish the HT room.
     
    #16 Negatron, May 17, 2019
    Last edited by a moderator: May 18, 2019 at 9:37 PM
  17. Michael Scott

    Michael Scott Moderator / Reviewer
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    the things that keep us up at night lol
     
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