Fix your Audio Ground Loop Buzzes and Noises

Started by admin, November 21, 2009, 06:43:53 AM

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Fix your Audio Grounding issues

Hiss /frying sound is a common  result of modern  audio ground loop noise using modern  gear with energy efficient switching power supplies -like GR-55, VG-99, SY-1000, GT-100, GP-10, etc

Download and read this 43 page paper on taming ground loop noise;topic=2078.0;attach=8699

Yohocoho wrote>
Hello everyone. I am very VERY happy to say I've sorted out my buzzing problems after trying to figure out how to route my VG-99 sounds to more than one amplifier (for stereo effects), to my PC (for music production) and its sound system, and to my studio monitors. Maybe you'll find this helpful if you too are experiencing annoying buzz.

I tried everything that everyone else had tried and blamed everything from light switches, wi-fi, TV's, computers, etc. etc. No joy! After reading lots on the net it seemed I had all the symptoms of ground looping. Lots of expensive devices can be found claiming to elimiate buzz. I resigned my self to spending a few bucks and trying the cheapest solution from Radio Shack (The Source) AND IT WORKED!!!! Check out the GROUND LOOP ISOLATOR ADAPTER at  for details.

As soon as I placed these between the VG-99 and every amp/studiomonitor/pc my buzzing stopped! I bought 2 of these Ground Loop Isolator Adapters and some plug adapters (so I could plug directly into my 2 amps) and NO MORE BUZZING (and as an added bonus it eliminated the buzz between my PC and my studio monitors!).

I had been frustrated for a couple years with the "fantom" buzzing and now all is quiet when I am quiet (except for the occassional hiss from my Godin Guitar on some acoustic patches). Save yourself some time and money and try this out for yourself. The Source sales guy told me I could return the Ground Loop Isolator Adapter and get my money back if it didn't work so long as I didn't damage the packaging. IT WORKED WELL!

Good luck!



That solution above is certainly cost effective for many folks.

Its basically  2 audio isolation transformers in a cable with RCA phone connections.

Another unit with same strategy is here:

Ebtech HE2PKG Hum Eliminator (2-Channel)
Eliminates ground loop hum. Converts back and forth between balanced and unbalanced signals.

The benefit of the Ebtech box is you may use TRS balanced connections  - simply insert the Ebtech between your VG-99's TRS Outputs and your target amplifier.




Or these with Jensen transformers and balanced I/O;

The transformer quality in those thing DOES have a huge impact on the sound quality.


I hate wall wart power supplies and might be coming from there.
I have a StompIO  RC-50 and Live 5 all hooked together and all have wall warts.
Im running it all into a 1402-VLZ3 mixer to some JBL PBX612M
Its not real bad but I think I can do better.

What is the best way to hook up all this stuff and keep the hum down.
A real good power strip with some type of filter?
What is the best thing to buy to clean up these ac lines and power supplies
and where can I buy it?

I want to add a GR-55 to the mix after I get this hum stuff cleaned up with what I have right now.



Its a classic case of several unbalanced Audio devices and several electronic Switching "green energy saver" power supplies - this spells disaster for most folks.

In your scenario above, you will likely suffer with situations of white noise hiss, which is a result of a Ground Loop.

I know, I know  - most folks think the only noise that occurs during a Ground Loop is 50/60 hz or 100/120 hz "Hum" - but since 2005, most electronics are forced to ship with "electronic Switching "green energy saver" power supplies " - and when a Ground Loop occurs with these type supplies, you will experience lots of Hiss and White noise instead of Hum.

If you were a skilled electronics technician you could add unbalanced to balanced audio converters at every Audio I/O point - but thats not practical.

To debug the noise, reduce the rig to the fewest parts   

1) Use XLR Cables and connect the main Output of the Mackie 1402-VLZ3 Mixer to the XLR input JBL PBX612Ms. listen to the noise.

2) Use TRS three conductor Balanced 1/4" cables and connect the Digitech Live 5 to a pair of inputs on the  Mackie 1402. Listen to the noise.

3) Repeat steps above as you add each new additional device (StompI/O, RC50, etc) and listen to the impact that has on your overall noise floor.

4) If you discover one device generates a lot of noise as soon as its connected, you may add a Hum-X power supply conditioner on the problem power supply.

5) Or you may insert an ART DTI Hum Eliminator on the Audio signal path between the problem device and the Mackie Mixer.

6) The Goal is to use Balanced Audio Connections whenever possible!!


I bought some of the best audio cable you can buy 95% shield. Its pretty good but just want to see if I can
clean it up a bit better. I notice when I move the wall warts around plugged into a power strip which is pretty cheap.
I can hear a change in the hiss noise. Its not a low pitch hum but like you say a hiss and maybe a little hum. Which my old Fender Twin reverb
had years back when I turned it up. This is really better but I just want to see if I can clean it up a bit more.
Do they make a power strip unit with built in filtering like in that Hum-X power supply conditioner?
I think I need to plug the wall warts into some alot better then that cheap power strip I have them in right now.
I have had to deal with some hum and hiss noises in my Ham Radio hobby but always was able to fix it.


maybe this might help

Reposted from Tom Engdahls' ePanorama Blog:

"Listening to ground loops

There is a way to "hear" the potential in different parts of your system. The method for checking audible noise is to take an amplifier and some magnetic field picking sensor. You can use a coil connected to a microphone amplifier. Or you can take an old cassette player, remove the magnetic pickup that reads the tape, put it on the end of a long stick.

Now just use headphones to listen to amount of noise on different parts of your audio system wiring. What should happen is that you will hear the stronger electromagnetic field at certain points, usually where the biggest problems are because more the current flows more magnetic field it generates. Often you hear also other noise sources like magnetic field mains transformers, so be careful to analyze when the noise comes from wiring that is part of ground loop or some other source not related to ground loop. The "hear" method is worth to try as an additional tool in trying to solve ground loop issues. "


Diagnosing and Fixing Ground Loops to Prevent AC Hum/Buzz
<from G-Lab Tips>

Ground Loops

In order to build the guitar systems without the hum you have to know how the ground loop arises and when it will be the 'hum' cause. 'Hum' is the sound which occurs after amplification of the voltage induced in cables by the disturbing electromagnetic field. Disturbing EMF is generated near to supply transformers, and sometimes even near to supply cables with the flow of big current (e.g. 50A). The bigger the transformer power (and its size and weight) the bigger the disturbing field.
Fortunately intensity of this field drops considerably along with increasing the distance. For example the typical 100 Watt tube amp supply transformer mostly interferes in space up to 1 meter around itself but in 2 or 3 meter distance the field is almost completely omitted. It is easy to check it with the single coil pickups guitar.
But what is exactly the ground loop?
The ground loop is any fragment of our system in which the ground wires (signal or power cables) make the closed loop (in other words the coil).
If such a coil is enclosed by disturbing electromagnetic field there appears in it the current induced by that field. This current puts on the signal cable ground the voltage which generates audible hum. It is particularly heard when we use the high gain (overdrive channel). There is also another rule – the bigger ground loop size the bigger hum we hear.

How to avoid the ground loops?

Firstly, building the systems you have to do it avoiding appearance of the ground loops. Especially those which are related with the amp as an amp has always the supply transformer inside.
The best way is to draw your installation scheme to see at once where the ground loops are.
You have to remember that inside of some devices there are used the isolating elements in order to avoid the potential ground loop. For example every of MIDI connections is not the galvanic one because just after the MIDI IN connector there is an opto-isolator which provides the isolation. Similarly to the relay type outputs (SWITCH OUTPUT) in the controllers (e.g. G Lab GSC) where the isolation is provided by the electro mechanic relay. More complicated is situation with the multioutputs power supplies for guitar effects even though many of the producers indicate exactly where the isolation occurs (e.g. G LAB PB-1). In many devices there are the switches named GROUND SELECTOR or GROUND LIFT that serve to eliminate the ground loops and are also necessary because lack of the connection with the ground makes also the hum problem. You have to remember also that ground loops appear also due to the supply cables containing protective wire (Protective Earth named ,,grounding"). Guitar tube amps posses a connection between signal ground and protective wire which you have to remember about. That's why connecting the guitar simultaneously to two amps by regular A/B/Y switcher creates the ground loop and hum.

Please notice that not every ground loop makes the 'hum' herable. If it is small size (e.g. between the devices in pedal board) and there are no bigger transformers (>10W) in pedal board and around it, you will not hear that a ground loop exists even on the high-gain.

If we use an amp and stompboxes the ground loop arise mostly from connecting to common supply the effects placed between the guitar and an amp input and the effects connected to the amp effect loop.

You have to pay attention with preamps and other devices (rack effectors), which features a power supply with ground (PE connector). If the PE wire is connected with signal ground (as it is in many preamps) and our amp or power amp also has a connection between PE wire and signal ground there will appear a ground loop (more or less hearable). Good solution in such case is to use low resistance (of shield ground) signal cable.

An example of a ground loop which appearance is not always hearable is connecting to the amp FX loop the effect. You will not hear the hum of the ground loop with high signal level on the loop (it is not always so) and which signal (SEND and RETURN) cables connected to the effects are placed as near as possible one to another (the best way is to stick them every 20 cm with plastic band clip on the final stretch near the amp).

Basic rules of building the guitar system:
1.    to the effects system situated between the guitar and the amp input from the system with the effects connected to the effect loop (there shouldn't be connection between them e.g. by the power supply or looper),
2.    the connection of earth with the signal ground should be only in one device (usually in the amp). In some devices e.g. power supplies or "bigger" effects the supplying wire has the protective contact but mostly it isn't connected or connected thru the resistor (from 10 to 50 ohm) with signal ground,
3.    to use the effect power supplies with isolated outputs to supply the particular effects,
4.    to supply from the same voltage source (if necessary) only the effects and other system elements that are in the same fragment of the system (e.g. on the effect loop),
5.    to keep the distance between or to isolate the metal cases of the JACK connectors to prevent from the accidental connection with other ground – especially that from footswitches and amps controlling signals.




More good info on Audio Ground Loops and linked Ground Loop Seminar from Bill Whitlock of Jensen Transformer

Isolate Ground Loop
Posted on February 26, 2013 by Nathan Lee Hicks

I've always thought of ground loop isolators, the type that they sell at RadioShack, to be crude and temporary solutions to problems that should be fixed with balanced audio circuits. This is why I was so intrigued to read through Bill Whitlock's Seminar on Ground Loops.

Bill Whitlock is a name that you can't avoid if you spend much time in the audiovisual industry. Originally I thought Bill had something to do with Whitlock, an AV integration company, but that is a different and equally well-known Whitlock. Bill is a brilliant engineer. He holds two patents related to balanced audio circuits and AC voltage regulation. However he takes educating very seriously. He could have easily made it by in life without educating, so I have to assume that it's a labor of love to bring neophytes up to speed. It probably doesn't hurt his company, Jensen Transformers, brand either.

I've never considered a ground loop isolator the optimum solution for a problem. I've even worked on designs where a senior consultant spec'd unbalanced passthrough audio plates with input transformers (ground loop isolators) at the rack. The solution at the time seemed ungainly, a value-engineered approach to a problem that should be solved with balanced audio circuits.

So I was shocked to read his paragraph about why powered balancing circuits aren't as great as I thought they were.

A wide variety of commercial interface devices are "active" (i.e., powered) devices. Although they incorporate many useful features, they invariably use differential amplifier circuits to "isolate" their unbalanced inputs. As explained later, the ground noise rejection of ordinary differential amplifiers is extremely sensitive to impedance imbalances in the driving source. With unbalanced sources, their entire output impedance becomes "imbalanced" and typically ranges from 200 Ohms to 1 kOhms or more. Under these conditions, the noise rejection of differential amplifiers is quite poor.

Some other highlights from his seminar:

Ground lifts should never be used to solve ground loop problems. Lifting a ground can be a serious safety concern. It's against code and can make you liable for any injuries that result. The reason is that if there is a fault in the neutral cable the ground provides a safe route for the current to return to the earth. This also trips the circuit breaker, so the short isn't prolonged any more than necessary. Ground lifts exist to provide a separate safety ground where a grounded power outlet isn't available.
When a ground cannot be provided you should use a ground-fault circuit interrupter or GFCI. "A GFCI works by sensing the difference in current between the line and neutral conductors. This difference represents current in the hot conductor that is not returning in the neutral – the assumption is that the missing current is flowing through a person. If the difference reaches about 5 mA, an internal circuit breaker is tripped."
Ground loop isolators, aka transformers, come in 2 flavors: output and input transformers. Input transformers use Faraday-shielding which eliminates capacitive couplings between windings. Magnetic fields may still pass otherwise current wouldn't be induced on the isolated wires. Output transformers attenuate low frequencies in the audio signal more than input transformers.
There is something called parasitic capacitance between power lines and the ground within equipment. Basically the insulators that separate the power lines in equipment from the chasis and signal ground function as capacitors. Capacitors in series with an alternating current function as a high pass. These parasitic capacitances can contribute to the overall ground loop problem.
Protective ground connections for Cable TV should be made to the same earth rod used for utility power, but it may not be. This is a problem because the earth is not a perfect conductor. Not even close. Soil has resistance which allows voltages to develop across different grounding rods.
This image in particular caught my attention.

This is how Bill Whitlock illustrates a ground loop in his seminar.

40" Samsung TV

For weeks I've been living with a problem with my TV sound system. The problem started when I decided to upgrade my speakers. I had been using a pair of Mackie 824 studio monitors from my audio engineering days as my computer speakers. I decided they would be put to better use if I used them as my television speakers, especially after purchasing an Apple TV. Now I regularly listen to music on the couch rather than in front of my computer. So I moved the speakers over and connected them to the direct output from the television which is just two unbalanced RCA jacks. The input on the Mackie speakers is balanced, so this irked me a little bit. On top of that the remote control would not control the volume of this output.

Mackie HR824s

I discovered a headphone output on the side of the TV, and although the output is still unbalanced it worked perfectly with the TV volume control. Aside: no consumer TV has a balanced output, and I'd even be surprised to find a professional one that does. Unfortunately when I powered on the speakers and adjusted the volume to a comfortable level there was a terrible hum. What made it so terrible is that it sat at this perfect level where it would interfere with quiet music. It wasn't loud enough to abandon the approach completely, but it wasn't quiet enough to ignore. I tried to optimize the gain structure by turning the volume of the TV to 100% and turning down the speaker input trim. This actually improved the hum to the point of being quiet enough to ignore in most circumstances. However the program audio would distort in loud portions of songs, movies and TV shows. This distortion fell into the same goldilocks range of annoying. There was no sweet spot to be found. I tired the TV volume at 75% and the speaker input trim a little higher. Distortion and/or hum could not be avoided. I actually found that the hum was less noticable on the direct out of the TV, so I left them plugged into that output. The problem with this approach was that I had no volume control unless I initiated Apple's "AirPlay" from the computer. Then I could control the volume from the computer, but otherwise the volume was uncomfortably loud until I played classical or other equally quiet, dynamically rich, music. To make matters worse the speaker input trim is an inaccessible little knob that looks like a screwhead on the rear of the speakers.

So I left it that way for weeks. If I wanted to listen to those speakers I would have to mute the integrated TV speakers. Turn on my Mackie speakers. Then initiate AirPlay from my computer in order to have the necessary volume control.

Now refer back to that ground loop illustration from above. When I saw this something clicked, and I realized that a ground loop isolator could fix my problem. I'm in a multi-tenant apartment building, so I have no idea how they have the utility power ground and the Cable TV ground configured. Even if they were on the same earth rod the impedance difference in the CATV ground path and the utility power path would probably be enough to give rise to a ground loop with the help of parasitic capacitance issues that are inherent to all electronic devices. I stopped by a RadioShack an hour later, picked up their eponymously branded ground loop isolator, and plugged it in at home. At first I inserted it into the direct out of the TV. With my head inches from the woofer I could immediately tell that the low level hum was completely gone. Excitedly I added the RCA to 1/8? stereo trs adapter to the isolator and jammed it into the headphone jack. I was astonished. The audio was perfect. I wasn't driving the headphone amp to 11, so there was no distortion. The ground loop was gone, so there was no hum or noise at all. I could control the volume with the TV remote. How can this be possible? Such a simple fix. No balanced audio required.

The funny thing is that if I were less informed about audio I may have just gone to RadioShack and bought this ground loop isolator as a first step. "What's that? A hum exterminator? Do you have an extreme hum exterminator? Cause my hum is pretty bad. There's some distortion and noise too. Do you have a distortion isolater?"

So I'm here to say, you're not too good for a ground loop isolator. Recording studios use them for direct inputs from instruments. I knew that, but I didn't know the details of why, which is why I ignored them when my TV sound system gave me problems. Even Bill Whitlock, the innovator behind modern balanced audio circuits, calls ground isolators a silver bullet. "Use ground isolators at problem interfaces. Isolators are a 'silver bullet' solution for common impedance coupling, which is the major weakness of unbalanced interfaces."

Silver bullet. I didn't even bother with getting a high quality input transformer. That may peev Bill as a representative of Jensen, but for my purposes it was all I neede


I used to always keep one of these in my gig bag, just in case...  It's still readily at hand in the home studio.


A poormans Ebtech Hum Eliminator   - Pyle PHE-400 $22

Unbalanced lines are more susceptible to picking up electrical noise and RF interference than balanced lines - the longer the unbalanced cable, the greater the chance of a problem. Using this device to connect two pieces of equipment is one of the most cost-effective ways to convert between unbalanced signals and true balanced signals. Automatically translates signal voltages to match difference in ground potentials.

60Hz Noise Removal
Removes AC Hum Noise
Breaks Ground Loops Safely
Maintains Highest Sonic Quality
Passive Device: No Power Required
High-Performance Ultra-Compact Design
1/4" TRS and XLR Inputs and Outputs on 2-Channels
Audiophile High-Quality Components and Exceptionally Rugged Construction
Automatically Converts Unbalanced to Balanced Signal Without Any Signal Loss
Uses 1:1 Isolation Transformers to Break Loop Antenna and Balance Audio Lines
Automatically Translates Signal Voltages to Match Difference in Ground Potentials
Weight :1.1 lbs.

Pyle PHE300 is $14

And read the "Must have Accessories for Mobile Guitarists - which lists a similar isolation transformer for stereo 3.5mm TRS Line level connections.

Reduces hum from your car´s electrical system
Provides a direct connection to your car´s AUX (auxiliary) port for pure sound
Cable braiding for strength, durability and limited tangle
4-ft long, 3.5mm audio cable


The Ebtech Hum Eliminator product line address computer  audio noise issues.

For an alternative - I recently ordered Pyle audio equivalents that also solve noise problems well.


Okay stupid question - so if I use a passive device with a 1:1 transformer I get a balanced output without losing voltage?

BTW the Ebtech hum eliminator I have is just a power outlet, so I will have to buy something.


QuoteOkay stupid question - so if I use a passive device with a 1:1 transformer I get a balanced output without losing voltage?

QuoteBTW the Ebtech hum eliminator I have is just a power outlet, so I will have to buy something.

I advise try this one  - zero gain loss. ($33 at Amazon)


I have a similar problem but it does'nt involve  ground loops.

When i connect the USB cable from my desktop computer to my Roland  Br 800  or my VG-99  connected to  my Yamaha console, i get a high frequency  whine  (around 10k hz ) only when  i launch  windows media player or I tunes   it doesn't matter witch one ,  its driving me crazy!!   the noise  is more apparent when the player is sitting idle.

Now If i use my laptop  running with  its own power supply  and connect the same equipment  i get no whining sound!!.

I have tried everything to my knowledge  and still  cannot  get rid of the whining sound. I even put these  snap on ferrite chokes  over the usb cable  with no luck!
I suspect  the switching power supply in my desktop computer!

Funny thing thaught!   if i play mp3's  thru the sound card inside the computer   i don't get that dreadfull  10 khz background noise!.
Any idea's  would be helpfull.



The 10k HZ whine is from the switching power supplies  employed in computers when a Ground Loop is present.

USB Noise - audio output has enormous noise with USB cable connected


Funny thing you mention about switching power supplies,  my laptop  also uses a switching power supply but the units power cord only has 2 prongs  one of witch is keyed for polarity and does not  have the round pin for connecting to the  wall plug.

my desktop computer  uses an inboard switching power supply but  the power cord  has 3  pins.
I wonder if  i isolate the round  pin  the whining noise will disapeer! , here in canada and in my house  the 2 prong plugs have a  keyed pin,  IE:  one wider pin and a  normal pin, impossible to reverse  in the wall outlet,  i have tested  all my outlets   with a voltmeter  to make shure  no voltage is present on the wider  slot, witch is supposed to be  Neutral!  and not  LIVE!.

Note that i only hear the whining noise  when  i connect the USB  cable from the desktop computer to my Roland BR800 to my yamaha console.

I'm not shure if the vg-99  would produce the same whining  sound if connected to the yamaha console.

I hope to get rid of this whining noise  cause its drivin me up the Wallbagner!!  lol!


Insert a passive DI box with ground Lift between your Guitar MFX and Yamaha Console should solve the 10kHz noise.

We are used to thinking Ground Loop Noise is 60/120  50/100 cycle

But since 2005 with the "Green Energy Saver" power supplies - the maddening whine of these new Switching supplies rears its head far more frequently.


Thankz for the headsup  Man i appreciate it!

Jean pierre


Unrelated, but tangental...   Building up to a question...   

Our practice studio is not grounded.  I had a discussion with a musician who said then you must have lots of ground loop hum.   I said no, in fact, none; ground loop hum has nothing to do with whether your 3rd prong works or not.  (I tried to explain what I read above, but apparently I was unconvincing...) 

My understanding is they are two COMPLETELY different problems, both involve the word "ground", so folks confuse 'em.

Now, I told him, the *real* problem with a lack of ground is that we are vulnerable to shock if:
  - Faulty wiring inside some gear, if it blows or frays & somehow the hot connects to the casing inside; you touch the case & become the path to ground
  - Atmospheric issues, not just the obvious lightening but bad weather can buildup a differential; static can get out of hand; you touch the case & become the path to ground

So...  Now I've convinced myself we've been lucky.  There's gotta be 20 metal-enclosed devices in there, non grounded.  Sooner or later a device will have a wiring issue, and one of us will get zapped.  Landlord is working on it; not too surprisingly, it's taking a while. 

My question:  Will a powerstrip (Tripplite or similar) with a GFI (ground fault interrupter) make the environment safe until it's fixed?  Should you have one on hand in case you gig at a small venue without proper grounding?
Address the process rather than the outcome.  Then, the outcome becomes more likely.   - Fripp


Quote from:  shawnb on December 08, 2014, 01:38:56 PM
My question:  Will a powerstrip (Tripplite or similar) with a GFI (ground fault interrupter) make the environment safe until it's fixed?  Should you have one on hand in case you gig at a small venue without proper grounding?

As an FYI if anybody else has this grounding (not ground-loop) related question...   

Yes, a GFI is an acceptable solution to this problem.   It will protect you from closing the circuit, i.e., getting electrocuted. 

And yes, a GFI & GFCI are the same thing.

Note that your 3-prong outlet tester will not work on ungrounded GFIs, since your tester uses the ground wire. 
Address the process rather than the outcome.  Then, the outcome becomes more likely.   - Fripp


Quote from: Elantric on December 08, 2014, 07:43:53 AM
Insert a passive DI box with ground Lift between your Guitar MFX and Yamaha Console  reduce power supply switching "hiss" noise - that can occur.

We are used to thinking Ground Loop Noise is 60/120  50/100 cycle

But since 2005 with the "Green Energy Saver" power supplies - the maddening whine of these new Switching supplies rears its head far more frequently.
Will this work properly if connected to the XLR out on my Alto TS112A or should I go out directly from my GR-55? Thanks


Insert a passive DI box with ground Lift between your Guitar MFX and PA / Active Powered Speaker to reduce power supply switching "hiss" noise - that can occur.

QuoteWill this work properly if connected to the XLR out on my Alto TS112A or should I go out directly from my GR-55? Thanks

Alto TS112A  onboard D.I. XLR out  has a Ground Lift switch, which I would employ when using the Alto TS112A as a stage monitor and  feeding the House PA