2:00 The green ground wire in a standard USA 120V residential electrical system goes back to the same place (the neutral bus bar in the circuit breaker box) as the neutral wire. The "ground" wire provides a second, fail safe route back there in case of a short within the AC powered device. You might say that the "ground" wire prevents a human from being the ground in case a short within a device occurs and the outside of the device goes hot and a person touches it, causing the current to go through them, and the ground, to find it's way "home" so to speak. But, the ground (green) wire goes back to the breaker box and attaches to the neutral bus. That neutral bus bar in the circuit breaker box is grounded (for lightning strikes), but people saying, or giving me the impression, that the "ground" wire goes into the ground has kept me from understanding how AC really works until I recently really had to learn for myself.
I like your story about the power supply issue. Now at live gigs there are so many power supplies from phones, laptops, pedals, etc. There are random noise and buzzing sometimes and it's because of this. Not to mention everyone at concerts have their phones out. So we switched to Star Quad XLR cables and that did the trick.
Great video, but I feel it's incomplete. Yes ground loops happen, and can be solved as per your video. But what's REALLY happening? What specifically a hum? Why not a buzz? Or sometimes both? What's causing a sawtooth like wave to form and not a sine wave? Did it start as a sine wave then get cancelled and sort of turned into a triangle/saw? That's what I'd like to know. Thanks for the video. I feel it's half way there to the complete answer. I'll check out your course.
I have a modest home studio, but I’ve been reading about star grounding, was hoping you would mention something here, but do you have any other explanations of this for those of us that have the luxury of wiring scratch? Simply do a run or every audio dedicated outlet?
whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .nomatter which product used its all the same it disconnects the ground is this correct
I got the humming noise, my DAC and amp are on the same powerstrip but none of them have a ground pin. should I connect the chassis of my DAC to the signal ground on my amp? or wtf is happening
I have been trying the lift option on both my breakout usb sound card and my DI box, neither of which do anything to remove the ground hum. Does anyone know why the ground lift option wouldn't work? Is it because I might have multiple ground loop paths through my audio devices? I'm going to try the same power socket for the desktop and laptop in question tonight and see how that goes. My signal cables are decent quality and I am almost sure it's the 2 earth pinned computers that make the ground loop. Here's hoping...
whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .no matter which product used its all the same it disconnects the ground is this correct .if so then either ay still have the same level of risk of death by electrical shock
I am plagued by this ground loop that ruins my guitar playing lol. Have tried literally everything I can think of at this point and put a lot of time into solving it.. starts to feel hopeless. Especially with everything in the same socket.. could it be the power strip? could it be the fact the interface is powered by USB? who knows at this point all I know is most other people with a focusrite have no issues lol
That still does not explain what ground difference actually _is._ How does it generate an audible signal? Also, how does the signal from a DI box with "ground lift" get to _flow_ between the DI box and the mixer??
Maybe that answer is too late, but at least it is an answer. So, sound is basically just AC voltage, and technically in your outlet there is already 60/50hz "sound" and 60/50hz is how many times phase in your live wire changes from negative phase to positive(technically not like that but that just easy way to explain). Voltage is difference between potentials, if your Ground or Neutral wire is 0 volts and your live wire is 220, then your voltage is 220, but if your neutral wire isn't actually neutral and has like 10 volts on it, then voltage is 210 at that point. The thing is voltage on neutral can differ slightly between outlets because no connection, and no wire is perfect, and this difference creates two problems. First, now your ground has current running through it, it's most likely extremely small, but may be picked up by sensitive devices, like mic and line amplifiers. And second problem is that your ground is not 0 anymore, and ground is the base for your signal, imagine your sound at it's loudest make AC at 10 volts, if you'll have even 1 volt ac on your ground, then even then signal is 10 volts at any frequency(or multiple frequencies) your base is moving 1 volt up and down 50/60hz so basically 10% of your sound volume will be this 60 hz hum(reversed in phase to line btw, but this is not important.. Is like you measure height and your ruler change it's length all the time, you measured that at this point there was 10 at the ruler, but next time you check it's 9 in the same place.
And for Di box, ground is just a wire which conduct electricity to place which can accept current, usually, you quested it, literal ground, in sound ground is reference, just something to compare signal to. it doesn't matter there this reference comes from, if it's constant across devices then it's fine.
Yet another incorrect explanation. The 50 or 60Hz hum doesn't come from "Earths at different potentials" it comes from magnetic fields in the area of the loop which are then introduced to the signal circuits by common impedance coupling and amplified. If mains outlet Earths were at different potentials it would mean that a current is flowing between them and that would cause an RCD to trip. Yes, there is a slight difference caused by a single coil pickup, but it is microvolts like the output of a ribbon mic. The real problem is mixing unbalanced and balanced equipment and not conforming to AES48 recommended practise. Many products confuse the difference between a signal common and a chassis screen, both should be connected to mains Earth, but not randomly. The screens of balanced cables should only be connected to chassis and not the signal commons. You connect to the planet for safety and discharging induced charges, but it should not be part of the signal circuit except as a potential reference. (Non static) Electricity flows in circuits, it does not flow to the planet like water. Note that I have not used the word "ground" to explain this, once you do that people can't see the distinction.
The delineation of electrical ground being a diversionary safety path for electricity in case of a fault as opposed to the signal low end-sounding ground was itself alone worthy of a sub. No one has ever put it that simply and accurately.
![ละลาย (LALALYE) - DAOU PITTAYA ต้าห์อู๋ พิทยา [OFFICIAL MV]](http://i.ytimg.com/vi/wo6r9TgausI/mqdefault.jpg)
This is an EXCELLENT video. David Wills is a mastermind.
Anyone who does audio needs to watch this.
This is a perfectly detailed and informative presentation! We'll done and thanks for sharing 👍🏾
2:00 The green ground wire in a standard USA 120V residential electrical system goes back to the same place (the neutral bus bar in the circuit breaker box) as the neutral wire. The "ground" wire provides a second, fail safe route back there in case of a short within the AC powered device. You might say that the "ground" wire prevents a human from being the ground in case a short within a device occurs and the outside of the device goes hot and a person touches it, causing the current to go through them, and the ground, to find it's way "home" so to speak. But, the ground (green) wire goes back to the breaker box and attaches to the neutral bus. That neutral bus bar in the circuit breaker box is grounded (for lightning strikes), but people saying, or giving me the impression, that the "ground" wire goes into the ground has kept me from understanding how AC really works until I recently really had to learn for myself.
I like your story about the power supply issue. Now at live gigs there are so many power supplies from phones, laptops, pedals, etc. There are random noise and buzzing sometimes and it's because of this. Not to mention everyone at concerts have their phones out. So we switched to Star Quad XLR cables and that did the trick.
Midas M32 is a clean and easy board, I love ‘em!
Thank you!! I want to learn more about the ISOLATION TRANSFORMER
Stuck tongue in toaster, hum went away, it works !
thanks - we have a show tonight, will try that
Man. Thank you. You explain it just excellent. Specifically with image with the samr outlet for two devices
fantastic explanation! I understood exactly what I was missing ♥
Great video, but I feel it's incomplete. Yes ground loops happen, and can be solved as per your video. But what's REALLY happening? What specifically a hum? Why not a buzz? Or sometimes both? What's causing a sawtooth like wave to form and not a sine wave? Did it start as a sine wave then get cancelled and sort of turned into a triangle/saw? That's what I'd like to know. Thanks for the video. I feel it's half way there to the complete answer. I'll check out your course.
I have a modest home studio, but I’ve been reading about star grounding, was hoping you would mention something here, but do you have any other explanations of this for those of us that have the luxury of wiring scratch? Simply do a run or every audio dedicated outlet?
Very helpful, thank you sir!
Thanks for the video.
whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .nomatter which product used its all the same it disconnects the ground is this correct
I got the humming noise, my DAC and amp are on the same powerstrip but none of them have a ground pin. should I connect the chassis of my DAC to the signal ground on my amp? or wtf is happening
6:41 *???* *Let's* *talk* *about* *phase* *........* *????????????????????*
I have been trying the lift option on both my breakout usb sound card and my DI box, neither of which do anything to remove the ground hum. Does anyone know why the ground lift option wouldn't work? Is it because I might have multiple ground loop paths through my audio devices? I'm going to try the same power socket for the desktop and laptop in question tonight and see how that goes. My signal cables are decent quality and I am almost sure it's the 2 earth pinned computers that make the ground loop. Here's hoping...
Thank you
whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .no matter which product used its all the same it disconnects the ground is this correct .if so then either ay still have the same level of risk of death by electrical shock
Ground lift switch is something different.
Do not break the third pin off.
I am plagued by this ground loop that ruins my guitar playing lol. Have tried literally everything I can think of at this point and put a lot of time into solving it.. starts to feel hopeless. Especially with everything in the same socket.. could it be the power strip? could it be the fact the interface is powered by USB? who knows at this point all I know is most other people with a focusrite have no issues lol
Hello thank you so much for sharing this information
thank you!
Sir , there is noise from speaker when any electrical switch is on or off , can you suggest solution for it ?
wtf then there is currently leaking from your amp aka faulty equipment might be dangerous
6:28 looooooool
Guitar connected to mixer also makes noise eventhough guitar not connected to a plug point. Why this happen
I haven't tried it yet but I don't think toasters would taste very good
That still does not explain what ground difference actually _is._ How does it generate an audible signal?
Also, how does the signal from a DI box with "ground lift" get to _flow_ between the DI box and the mixer??
Maybe that answer is too late, but at least it is an answer. So, sound is basically just AC voltage, and technically in your outlet there is already 60/50hz "sound" and 60/50hz is how many times phase in your live wire changes from negative phase to positive(technically not like that but that just easy way to explain). Voltage is difference between potentials, if your Ground or Neutral wire is 0 volts and your live wire is 220, then your voltage is 220, but if your neutral wire isn't actually neutral and has like 10 volts on it, then voltage is 210 at that point. The thing is voltage on neutral can differ slightly between outlets because no connection, and no wire is perfect, and this difference creates two problems. First, now your ground has current running through it, it's most likely extremely small, but may be picked up by sensitive devices, like mic and line amplifiers. And second problem is that your ground is not 0 anymore, and ground is the base for your signal, imagine your sound at it's loudest make AC at 10 volts, if you'll have even 1 volt ac on your ground, then even then signal is 10 volts at any frequency(or multiple frequencies) your base is moving 1 volt up and down 50/60hz so basically 10% of your sound volume will be this 60 hz hum(reversed in phase to line btw, but this is not important.. Is like you measure height and your ruler change it's length all the time, you measured that at this point there was 10 at the ruler, but next time you check it's 9 in the same place.
And for Di box, ground is just a wire which conduct electricity to place which can accept current, usually, you quested it, literal ground, in sound ground is reference, just something to compare signal to. it doesn't matter there this reference comes from, if it's constant across devices then it's fine.
Thanks. Problem solved!
This dude's funny
i live in europe and we dont have the ground pin and i have both devices connected to the same outlet but i still have buzzing?
In EU we have those metal things at the sides of the socket, not the 3rd PIN.
To live in Europe and not know electric circuits are grounded?
Ironically, that's nearly how they made that sound for the lightsabers.
cool fact
Issue resolved by using a ground lifter.
75000 dollar ht system broken. 9 dollar used ground loop isolater from amazon= FIXED
Yet another incorrect explanation. The 50 or 60Hz hum doesn't come from "Earths at different potentials" it comes from magnetic fields in the area of the loop which are then introduced to the signal circuits by common impedance coupling and amplified. If mains outlet Earths were at different potentials it would mean that a current is flowing between them and that would cause an RCD to trip. Yes, there is a slight difference caused by a single coil pickup, but it is microvolts like the output of a ribbon mic. The real problem is mixing unbalanced and balanced equipment and not conforming to AES48 recommended practise. Many products confuse the difference between a signal common and a chassis screen, both should be connected to mains Earth, but not randomly. The screens of balanced cables should only be connected to chassis and not the signal commons. You connect to the planet for safety and discharging induced charges, but it should not be part of the signal circuit except as a potential reference. (Non static) Electricity flows in circuits, it does not flow to the planet like water. Note that I have not used the word "ground" to explain this, once you do that people can't see the distinction.
now explain this to me like I'm 5 years old
same ground is not solving the problem
Just plain wrong
that's one way to put it...
could also say, "erroneous"
or maybe, "not completely correct" to soften the blow a bit, no?
How is it wrong, can you explain please? I'm getting a headache
Using isolation transformer makes grounding useless anyways. so remove the grounding pin.
Never cut off a ground pin.
The delineation of electrical ground being a diversionary safety path for electricity in case of a fault as opposed to the signal low end-sounding ground was itself alone worthy of a sub. No one has ever put it that simply and accurately.