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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: kennytroy on June 12, 2018, 08:47:06 AM

Title: Impossible Ground Loop?? Tried for months.
Post by: kennytroy on June 12, 2018, 08:47:06 AM
Hello, first I want to thank you for reading this and offering any advice possible.

I have been struggling with a ground loop issue for months now since building my PC, and I have read nearly everything and tried 85% of solutions suggested on the internet - nothing seems to work.

I will give all relevant information as neatly as possible, followed by solutions I have tried.

My PC Build

Motherboard: TUF Z270 Mark II
Graphics Card: GTX 1050 Ti
Power Supply: EVGA 550 G3
Cooling: Corsair H60
Memory: 16GB TridentZ RGB (8gb x 2)
Processor: i7 7700k
Internal Soundcard: Audigy Rx
Monitor: Samsung CF591 27" Curved
Speakers: Yamaha HS7's

** Please note that I purchased my internal Audigy Rx soundcard as a "solution" after already having experienced this buzzing for several months via my graphic card's audio card.

How I'm Connected

I have a lot of wires running between my computer, monitor, and my TV which is wall-mounted directly above my desktop build.  I assumed this was a problem, so for simplicity I disconnected everything and only connected what is necessary to solving this problem.

Wall Outlet -> Power strip with three connections: (1) computer power supply, (2,3) power cords for both Yamaha HS7 speakers

I am connected from the speakers to my desktop via dual 1/4" to 3.5mm aux.

What I've Tried, What Doesn't Work

- Disconnected all other wires that are not my computer's power supply, and my two Yamaha HS7 speaker power cords, does not work
- Purchased an internal Audigy Rx soundcard, does not work
- I have tired three different outlets in my room, and even tried outlets in other rooms, does not work
- My computer is placed on a cardboard box so that it is not touching carpet, does not work
- Tried external USB adapter, does not work
- Tried a second pair of 1/4" to 3.5mm cables, does not work

Other Connections That Work
- Plugging the dual 1/4" to 3.5mm aux into my phone
- Plugging the dual 1/4" to 3.5mm aux into my laptop, with the laptop power cord plugged into the same [or different] outlet as the speakers

What the flying fuck is happening?

I am at a total loss. I was going to buy one of those Hum X ground loop adapters, but I am SO HESITANT to continue spending money on solutions that seem to not be working.

Is there a hardware problem?
Is it a problem with my 1/4" cables?
Is there incompatibility somewhere in the electricity field?
Am I totally fucked?

Thank you guys so much.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Ray Aberle on June 12, 2018, 10:41:36 AM
Hi Kenny,

Welcome to the Pro Sound forums! There's definitely a lot of great information on here to poke through. The downside is that we're mainly focused on professional audio systems and their associated power and grounding Best Practices and trouble-shooting. Based on the information you provided, and the fact that you don't have this ground loop problem when you plug any other source into your speakers (utilizing the same cables), it sure sounds like the buzz is being produced by something internal on the computer... and that's probably not something we'll be able to help you troubleshoot over the internet.

Don't give up hope- naturally, it's possible that someone on here might be able to give a pointer or two, but I wanted to make sure you have the expectations in mind, and you aren't frustrated if no one jumps on your thread to help. Computer troubleshooting just isn't the primary focus of the ProSoundWeb forums! :)

-Ray
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Len Zenith Jr on June 12, 2018, 11:55:04 AM
Have you tried headphones into your computer? Is there noise present? If no noise is present with headphones than an isolation transformer would most likely solve your problem. The ART DTI  (https://www.amazon.com/ART-DTI-Transformer-Isolator-Interface/dp/B0009GUOQA)is an affordable decent one, there are plenty of others out there too. If the noise is present with the headphones then you have problems with your computer.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Mark Cadwallader on June 12, 2018, 12:00:02 PM
Have you tried other speakers?  It appears you have the buzz or hum with the speakers, but none without.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Mike Sokol on June 12, 2018, 12:06:59 PM
Don't give up hope- naturally, it's possible that someone on here might be able to give a pointer or two, but I wanted to make sure you have the expectations in mind, and you aren't frustrated if no one jumps on your thread to help. Computer troubleshooting just isn't the primary focus of the ProSoundWeb forums! :)

-Ray

Kenny, I'm the moderator here and Ray is correct. We do focus on pro-audio issues, but that being said most of us will hook a laptop into a REALLY BIG set of speakers. So we can throw you some ideas you might not have heard yet.

#1) Get a cheap 3-light outlet tester from any big box store (less than $5) and test to make you have properly grounded outlets in the first place.

#2) Listen to the sound the speakers are making to determine if it's actually a hum (caused by an actual ground loop), or maybe a buzz (caused by a lack of shielding on a wire or a complete loss of ANY ground). A hum sounds like you're humming low b flat with your lips closed. But a buzz sound more like humming into a kazoo since there will be a lot of high frequency harmonics.

#3) The audio isolation transformer is a good bet, and that's how most of us in the pro-sound world connect our laptops into large sound systems with different grounding systems. Something like this would work: LINKY (https://www.sweetwater.com/store/detail/Hum--ebtech-he-2-2-channel-stereo-hum-eliminator?mrkgcl=28&mrkgadid=3274464273&rkg_id=0&product_id=Hum&campaigntype=shopping&campaign=aaShopping%20-%20Core%20-%20Live%20Sound%20&%20Lighting&adgroup=Live%20Sound%20&%20Lighting%20-%20Live%20Sound%20Accessories&placement=google&adpos=1o2&creative=250341283160&device=c&matchtype=&network=g&gclid=EAIaIQobChMIn4iQxcDO2wIV2oWzCh2BtAR2EAQYAiABEgJqwvD_BwE)

#4) Under no circumstances get an Hum-X ground isolation plug. I'm sure that's not your problem and it won't solve your noise issue. 

Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Jerome Malsack on June 12, 2018, 12:24:16 PM
Another choice Mike is ebtech he-2-xlr  that has the XLR and 1/4 TRS.  I like this for the pro and small band use for the active speakers as floor monitors in the Bars and small venues.  bands finding outlets to feed the power and not on the band power stringers.

This one does not require the special cables  xlr to 1/4 TRS and the xlr are locking so no unplugs when pulled.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Jerome Malsack on June 12, 2018, 12:46:51 PM
He also is stating that he has TV and may be a VGA connected to video display. 
If this has a coax cable from the Cable provider he might need a 75 ohm F connection ground isolation.   http://www.newark.com/mcm/4170/isolation-transformer-ground-loop/dp/54K3496?st=video%20ground%20isolation

Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Jonathan Johnson on June 12, 2018, 02:38:41 PM
Kenny, I'm the moderator here and Ray is correct. We do focus on pro-audio issues, but that being said most of us will hook a laptop into a REALLY BIG set of speakers. So we can throw you some ideas you might not have heard yet. 

I'll also warn you, Kenny, that you shouldn't disqualify advice given here without a solid explanation why you think it's invalid. The folks here can really rip into a person who insists on doing things the wrong way -- especially when safety is involved.

But, if you demonstrate respect, you can get fantastic advice here. These folks are professionals and they really want to help you do things in the best, safest way possible.

---

Computers are often a less-than-ideal environment for quality audio. A lot of EMF is generated inside of a computer, and that can be picked up by an internal sound card. Unless the analog circuitry of the card is well shielded (very few are), the audio can easily be contaminated by that EMF.

Further, the power supplies in many computers can "contaminate" the grounding within the computer with electrical noise, and if the shield of the analog audio output is connected in common with the PC's grounding, that electrical noise can affect the signal since the unbalanced connections of your PC use the shield as one of the poles of the signal. Isolation transformers may not resolve this noise.

Those issues are not "ground loop" noise. If your speakers and PC are plugged in to the same power strip and you still get noise (so that all devices' grounding is at the same potential) then you shouldn't get ground loop noise (though stranger things have happened). However, if your PC has faulty grounding, then you could get ground loop noise.

If you have a multimeter, you can perform a few tests. Set the multimeter to resistance/ohms. (usually denoted by the Omega symbol Ω ) Measure between the metal case of the PC (powered off) and the ground pin of the PC's power cord. It should read nearly zero ohms. If it shows no continuity, you have a grounding problem in your PC: either the cord or the power supply is faulty.

Another test you can do is power on your PC and the speakers (don't play anything), then set the multimeter to "AC volts". Disconnect the cord from the speaker, and measure for voltage between the "sleeve" of the 1/4" plug -- it's the contact closest to the plug body -- and the sleeve of the jack. You might have to poke the lead inside the jack to the contact closest to the outside. If you measure voltage here, that's a sign of a ground loop problem.

Of course, none of this really solves your problem, but it might help isolate and identify the problem.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Jay Barracato on June 13, 2018, 03:58:08 AM
Hello, first I want to thank you for reading this and offering any advice possible.

I have been struggling with a ground loop issue for months now since building my PC, and I have read nearly everything and tried 85% of solutions suggested on the internet - nothing seems to work.

I will give all relevant information as neatly as possible, followed by solutions I have tried.

My PC Build

Motherboard: TUF Z270 Mark II
Graphics Card: GTX 1050 Ti
Power Supply: EVGA 550 G3
Cooling: Corsair H60
Memory: 16GB TridentZ RGB (8gb x 2)
Processor: i7 7700k
Internal Soundcard: Audigy Rx
Monitor: Samsung CF591 27" Curved
Speakers: Yamaha HS7's

** Please note that I purchased my internal Audigy Rx soundcard as a "solution" after already having experienced this buzzing for several months via my graphic card's audio card.

How I'm Connected

I have a lot of wires running between my computer, monitor, and my TV which is wall-mounted directly above my desktop build.  I assumed this was a problem, so for simplicity I disconnected everything and only connected what is necessary to solving this problem.

Wall Outlet -> Power strip with three connections: (1) computer power supply, (2,3) power cords for both Yamaha HS7 speakers

I am connected from the speakers to my desktop via dual 1/4" to 3.5mm aux.

What I've Tried, What Doesn't Work

- Disconnected all other wires that are not my computer's power supply, and my two Yamaha HS7 speaker power cords, does not work
- Purchased an internal Audigy Rx soundcard, does not work
- I have tired three different outlets in my room, and even tried outlets in other rooms, does not work
- My computer is placed on a cardboard box so that it is not touching carpet, does not work
- Tried external USB adapter, does not work
- Tried a second pair of 1/4" to 3.5mm cables, does not work

Other Connections That Work
- Plugging the dual 1/4" to 3.5mm aux into my phone
- Plugging the dual 1/4" to 3.5mm aux into my laptop, with the laptop power cord plugged into the same [or different] outlet as the speakers

What the flying fuck is happening?

I am at a total loss. I was going to buy one of those Hum X ground loop adapters, but I am SO HESITANT to continue spending money on solutions that seem to not be working.

Is there a hardware problem?
Is it a problem with my 1/4" cables?
Is there incompatibility somewhere in the electricity field?
Am I totally fucked?

Thank you guys so much.
Power strip is always one of the first places I look for noise. Have you tested with the power strip removed?

Sent from my Moto Z (2) using Tapatalk

Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Kevin Graf on June 13, 2018, 09:14:34 AM
This 2012 Bill Whitlock seminar paper has an excellent section on troubleshooting:

An Overview of Audio System Grounding and Interfacing
by
Bill Whitlock, President
Jensen Transformers, Inc.
Life Fellow, Audio Engineering Society

Start at page 101.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Luke Geis on June 13, 2018, 06:05:39 PM
It's a ground loop issue for sure. It sounds like you may have whittled down most all other options. One thing I try to do if I get that issue is to plug the computer and the speakers into the same outlet utilizing an adapter that has three outlets form one plug. It eliminates the ground path potential at least from the power source point. If it still buzzes, it is likely one of the other units power supply just doesn't work well with others.

The simple fix is to get a stereo DI box that has the needed connections for you. Most DI's have 1/4" inputs and XLR outputs. This should be fine for your needs. Simply utilize a 1/8" stereo to 1/4" dual mono cable and connect to the DI, and then go from the DI into the speakers via XLR. Then flip the respective ground lift switches on the DI until the noise goes away.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Jonathan Johnson on June 14, 2018, 03:38:52 PM
The simple fix is to get a stereo DI box that has the needed connections for you. Most DI's have 1/4" inputs and XLR outputs. This should be fine for your needs. Simply utilize a 1/8" stereo to 1/4" dual mono cable and connect to the DI, and then go from the DI into the speakers via XLR. Then flip the respective ground lift switches on the DI until the noise goes away.

Or get a Peavey USB-P if all you want is to output stereo sound (not surround sound). Moves the digital-to-analog conversion outside of the computer; doesn't need drivers (installs as a "class" device using built-in drivers), works with PC, Mac, Linux; provides a transformer isolated, balanced output via XLR connectors. Street price $45-50.

Beware, though: some have a manufacturing defect where one of the channels has flipped polarity. Probably a miswound isolation transformer.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Sammy Barr on June 14, 2018, 03:43:31 PM
Try it with the computer unplugged. The ground pin causes issues. If it's not a laptop use a 2 prong adapter.
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Thomas Harkin on June 14, 2018, 03:51:55 PM
... use a 2 prong adapter.

I can't bare to watch!   :-[   :o
Title: Re: Impossible Ground Loop?? Tried for months.
Post by: Ray Aberle on June 14, 2018, 04:14:27 PM
We definitely need to have the OP swing back around on this.

Things like this:
Try it with the computer unplugged. The ground pin causes issues. If it's not a laptop use a 2 prong adapter.
are not helpful since the OP has already stated that it's most likely an issue with the computer source (The OP said the problem occurs when a) the computer alone is connected, but not b) a laptop is connected or c) a phone is connected-- since the problem occurs regardless of whether or not the laptop is connected to house power, it's fairly clear that the source power for the audio source is not a factor.).