I worked in the ROV industry. We sent control signals and video over umbilicals 1000 Meters or more in length. Ground loops and noise were serious issues as well as the risk of fatal electrical shocks. First we had our power supplied by an Ungrounded Delta Wired Generator. This eliminates a power return to ground making operations much safer for personnel and equipment and while this option really does not apply with sound equipment I supplied it to show sometimes the problems can be caused by normal safe practices. We eliminated or mostly got rid of our ground loop problems by isolating chassis or electrical ground from any signal ground or signal path or return. In some systems we could have as many as four different isolated grounds. The bad news is that signal voltages could float above normal electrical ground but there was no path for current to flow. I would like to see the professional audio and sound operators and manufacturers adopt this philosophy by using totally isolated signal paths eliminating ground loops by doing so.
This video just helped me with a year long problem in my guitar setup. I had been chasing the problem, not getting results, and about ready to move out of my house because that had to be the problem thinking i had tried everything else. Thank you so very very very much. I added a studio monitor to my sound about a year ago and plugged it into an outlet on the other side of the room. Today I changed it to match where my amp is powered. Thank you so very much.
A good video. In sound systems, howling, hum noise, ground noise, and oscillation (higher frequency instability) are big problems and each one has its own ways of being eliminated or attenuated. Oscillations sometimes have to do with amplifiers with very high feedback loops or with output and input lines to close to each other. Ground noise has to do with the so called ground loops while hum noise has to do with micro lines peaking up harmonics of line frequency that propagated by air or by AC lines to close to audio lines. Howling has to do with microphone and loudspeaker closed to each other or resonances in the space where the system is used. To attenuate this trouble we have to reduce sound level, reposition micro and speakers, use frequency shifters and/or equalisers. The PCB ground line is normally connected to the chassis somewhere and it is the main source of ground hum.This hum can be attenuated if we cut this direct connection (it is a short circuit) and connect both grounds through a wire wound resistor of about 10 Kohms having in parallel wit it a 2 MF ceramic, polyester, etc, capacitor.
What a great video. My set up is as follows - Macbook, connected to a wall powered mixing desk via a USB insert - in that mixing desk I have an XLR condenser mic connected, using another wall powered compression unit, connected through an insert on the same channel as the mic. No problems, no ground loop. The problem began when I tried to do something very simple, which was add a 3.5mm TRS to Dual 1/4" TS cable between the mixer and my DSLR camera,, so that the mic runs through the camera (for better lip sync on live stream/conferencing). Instant ground loop and very loud hum and buzz and I couldn't work out why. Now I know why. I'm using my DSLR camera as a webcam, which is also wall powered with a dummy continous battery - when connected to the mixer, this means I have two different wall powered devices running through it (the compressor and camera) which is obviously causing the loop (with the USB connected wall powered Macbook which may or may not be adding fuel to the fire). I've ordered one of those decoupling boxes and will expect that this will work, when connected between the camera and mixing desk. Fingers crossed.
Very knowledgeable description of my buzz/hum. The solution might be beyond my budget. Thank you for sharing your expertise. Based upon your explanation I tested a couple things. Unplugged all devices, mouse, external hard drive from the usb ports and unplugged AC too. When I move the AC cable close to its import connector or my computer the buzz grows. I'll have to record without it being plugged in. Thanks again for your help.
love your explanation, clear, crisp and correct.. as an electrical engineer, I appreciate the way you explain the balance signal with differentiate amp to eliminate noise while producing 2X the signal.. I'm hoping your next video is going to be about eliminating feedback with home entertaining system .. singing karaoke at home produced a lot of feedback, and I bought a few feedback destroyer devices, but none of them seem to help.. Thks..
I was having this problem a few months ago with our PS3 when I connected it to one of our stereos. Tried using grounded adapters for the outlet plug like someone on a forum had recommended, but that didn't work. Figured out that the AV cable was sitting on top of the power cable from the unit. I simply cut a small 3" length of pipe insulation (which I already had) and placed the AV cable inside of it, then let it rest atop the power cable, instead. Hum immediately went away and hasn't been back. Wish I had thought to do that, first; would've saved me a few bucks on something I don't use. :)
@@randinonsense7360 pipe insulation, it's a foam rubber sleeve like a pool noodle. I think it worked for him because it physically separated the two cables enough that the AV cable didn't pick up any EM radiation from the power cable.
excellent video!! I live on 4th floor in a 120 year old block of flats in Madrid. The 240 juice fluctuates on a daily basis . i dont think the earth cables get all the way to the bottom!! Thiis presentation was very informative . THANKS
After 10 or so hours of trouble shooting/investigating/self educating, this video made everything clear. We're going to take an old set of balanced trs cables and remove the ground pin on the trs connectors on the monitor ends. This will be our ground lift point for the two monitors. Configuration we have is computer tower - usb to interface - interface output via 1/4 inch trs to each monitor. Each monitor is self powered/grounded, so we have a ground loop between the monitors via the interface. Ground lift on the trs cables on the monitor ends should fix our hum/hiss/pops
Excellent presentation + clearest explanations. --- I have never found an explanation for similar problems in a 2 wire (AC) 220V European circuits, though. Are those boxes identical in construction and use? Is AC filtering done the same way, since they don't have 3d prong for ground? I thing that Alectro is the place to get answers and... to shop. Bravo!
Cutting signal wire ground could introduce RF noise due to antenna effects. However, these effects are (almost) non-existent in audio systems due to the cable and wavelength. Unless the system is >6km (λ/f) Cutting the signal ground but leaving the shield intact is the safest budget solution.
Great explanation of ground loops. Just being picky here but when you say '180 degrees out of phase' you are actually talking about opposite polarity. Phase implies a time delay, having the same signal just delayed half a cycle. Your statements get the point across but to be accurate you should use polarity.
Yes, opposite polarity. In-phase would imply exactly 180 (degrees) of phase, anything other than 180 (degrees) are referred to as "out of phase." Phase does not imply a time delay. If you calculate it 2 phases (1 cycle) at 60hz (60 cycles or 120 Alternating polarities a second. But your ear wouldn't hear this as a delay. Phase refers to a relationship between positive and negative polarity in the sine signal. As it pertains to microphones and pick-ups, out of phase would imply an auditory delay not a delay from a ground loop.
Indeed Douglas Sebens, it is a common misconception. It is not 180 degrees out of phase, it is inverted. However, the ground loop explanation is fundamentally wrong in this video, so not so great.. There is no potential difference between the earthing connections of wall outlets if no devices are connected to them. Once a ground loop is created (or any loop of electrically conducting material), a current starts to flow through the loop, creating the potential difference. And by the way, jon wilson, you're talking shit.. it makes no sense at all.
I used to work on sound systems for churches and my own church drove me insane with hum. Had to do many crazy things to get it down and quiet. What do you have going on???
Actually, this video helped me tangentially. It prompted me to look at the many connections in my modest shack and reconnect some of the AC feeds. This provided a modest improvement, so it seems that I am on the right track. It's still humming, since I couldn't pull the rascal out of the multi-tap feed. It's funny though, the problem of humming just suddenly appeared. It's freezing here ... nothing works ... time to call Ghostbusters.
Thanks for this tutorial has help me to understand how I should set my system up and what type of speakers leads I need use or devices to accompany as an option.
I've gone through the content along with conceivable way of explanation on subject & pattern of elaboration of issues & there causes & solutions. Big thanks for the same!!! It would more useful , if available in Hindi (Hinglish) language retaining of technical terms in English!!
I solved my hum. I used two channels of my Mixer/Amp, plugged the left and right RCA cords from my laptop into separate RCA to 1/4 inch phono jacks, one in each channel.
At 14:05, if the laptop's input is stereo (unbalanced) and I'll send signal to it from an unbalanced aux-send, how would you make the connection balanced? Thanks!
thank you very much for this video. i'm wondering if the DI box capabilities of audio interfaces can suffice or should a separate DI box be used because i still get nasty hum out of my electric guitar when i connect it to my audio interface to my laptop.
If a laptop has a ground loop, just unplug it from the wall and use battery. Also, there are other such transformers to break ground loops from Whirlwind, Radial, etc.
this video put me onto the right track to resolving my sound issues. my desktop had a major hiss, my laptop on battery power did not. thank you so much for this very informative video.
This sounds familiar. We had a problem for a while in our rehearsal space where I would get shocked if I touched my guitar strings and the cage of an SM58 at the same time. I assumed it was a ground loop between the mixer and my amp, so I just started mixing and matching outlets throughout the room, and found that as long as my amp was on the same power strip as the mixer, I could plug my pedal board (about 6 analog pedals daisy chained on a 9 volt power supply) into an outlet on a different breaker and avoid getting shocked. So I'm not sure exactly where the loop was, but I broke it somehow!
Thanks very much for the explanation. I have a few questions as follow: 1. If possible, please explain more of the differences between passive DI box and Active DI Box, which one is better and why? 2. I noticed at both active and passive DI box settings there is a button call GROUND LIFT, which one should we choose ("GND" or "Lift") in order to eliminate the ground loop noise? 3. In the DI box, may I know what is that "Attenuator/Attenuation" all about? And which setting should we choose (i.e. 0, -20 or -40?) 3. Can I simply use DI box for all ground loop problems instead of AGDC2? (because in my location I see only DI box available in all the music shops, never seen one like the AGDC2, never even heard it before.)
I have the Shure Wireless MIcs using XLR cable to connected BMB karaoke mixer input. It works fine, but want to add the compressor of BEHRINGER MULTICOM PRO-XL MDX4600. After connect them all together. IT have the hum sounds. So I think I need the DI box? if so, do I need just 1 DI box or 2 boxes since I currently have 2 mics? Thx
So, my chain looks like this: guitar->usb audio interface -> pc(running guitar rig/bias/etc). In this case there is a lot of hum,but some noisegates can handle with it, but when i add a preamp beetween guitar and audio interface no gate can help. Now,the question is - if it's the groundloop conflict and if a dibox may help solving this issue? Many thanks anyways
I have mains hum probably due to a ground loop between hi end hifi components connected to the same outlet. None of them have balanced inputs or outputs. If I used the unit you recommend surely it means I have to use more interconnects and wouldn’t it interfere with the purity of the sound in such a system? My DAC and transport are from China. Is there a chance this affects the situation in any way, by having slightly different voltages?
I have a balanced xlr that goes from a preamp pedal and into my computers soundcard which has a 3.5mm input. My question is....are line ins on soundcard balanced....unbalanced....or capable of handling either? Reason I ask is I have ridiculous noise and I'm trying to narrow down exactly where the issue is....without buying yet more things that ultimately have no or little improvement. I'm thinking a 3.5mm in line ground loop isolator might be the key....but I'm not certain.
Great video! I'm a street performer and I face humming when I plug my amp (battery powered) and my pedals (which run through a power bank), if I swap my eletric system for a car battery powering everything, would the humming quit?
Yes. But you would need to make sure about power consumption of both of those systems, as a sudden peak in each one would hinder the working of another one.
Hi, great video great explanation, subbed. I'm having a problem with my rig and beg for your help to understand what's the cause. I plug my guitar (Ibanez RG with two Humbuckers and one single coil, properly grounded and shielded) straight to my Line 6 POD HD500x (wich is powered by a two pins plug transformer (I'm in Europe, so, no ground connection) and then monitor it through headphones. I'm getting a 50 cycle hum that goes away when I touch metal parts of guitar or POD. What's the cause of the hum? Lack of ground connection to the wall socket?
although it is most likely your line 6, check if you're plugging the headphones to the designated output. If you're plugging it to the line out, or the main out that goes to your amp, that might be the issue. also, the line 6 has a ground connection, which you can plug some wire into or touch with a screwdriver. If none of this works, get a grounded plug. Because we have grounded plugs in Europe too.
I have a question, and I have no knowledge on AV, so I’ll try to explain my question the best I can, but at my church We upload the sermons live to Facebook, the audio for the video is what is coming from the board(not a separate mic) and there is a hum in the video audio, so how do I know if I need a 2 channel line level decoupled or a DI box?
Great video! Do voltage regulators help? My system also has a hum but only Ribbon Microphones bring it out clearly. As you described in the video, my 50ft. snake amplifies the hum signal very well. So I wonder if I plug all my equipment into a single Voltage regulator such as the APC LE1200, would that get rid of the hum?
+OZ B Just realized that I may need a Power Conditioner - not a regulator! Going to try the Furman M-8X2. Anyone else try that unit to eliminate hum and hiss?
What if I only have one device in the socket with no other devies interfering with it, but still get a ground loop buzz? The buzz also only happens with one guitar amp and not with others.
I've a turntable and an hi-fi both without earthing to wall. Other source devices are connected to the same wall power strip, noone with earthing. The grounding between these devices is linked through the unbalanced L+R phono cable with the earth thiny wire. Noise is present and follow the volume level. But still present if the turntable is disconnected from cable. With same speaker I've also tried two different hi-fi system. I can't figure out how the problem can be generated by AC and how any DI Box can be help in this scenario..?
Ground links should always be considered because of their uniqueness to the spere magnetism system...The audio line and ohm link is imperitive to understand.
So, I currently have an odd setup, so perhaps you can let me know a better way to deal with it. I have 2 different dacs feeding two different audio sources, when either is used individually, the ground noise is essentially zero, but when the two sources are merged, there is a horrible buzz. The signal is sent stereo via 3 wire, and I assume the problem is the shared 0v ground aren't the same on the two sources. One of the dacs is grounded to earth, but the other takes DC in and isn't ground referenced at all, i assume it functions on virtual ground. How would I mix together these two sources without the grounds clashing then causing hum? Basically, I am attempting to have two different audio sources play on the same set of speakers, without buzzing occurring when more than one source is hooked up at the same time. Currently my solution is use a 2 way toggle switch that I have to flip manually to switch between the sources grounds, but I hate this solution.
Is this normal to happen if you plug studio monitors directly into the wall? Would this be an issue within wiring within my house and could a power conditioner help here?
I get crackle sounds from just 1 speaker in my home theater since I added a 7ch amp. I can't seam to solve the issue. What should I do? Some told me to buy a conditioner. The amp and receiver are connected with unbalanced rca as the receiver doesn't have balanced xlr's. I also have the amp connected in a different outlet because when the amp was on the same outlet it was shutting off du to possible line sag.
My home theatre hums as soon as I turn it on regardless of if it's connected to anything else. I'm even using optical cable, so this should not effect it anyway. Do I just have a crappy speaker?
Roger Stevens It's a brand new Ibanez bass and a brand new Mark Bass amp. I bring it to my house and plug it up; no hum. I take it to where I play it, plug it up; constant hum. I've tried ground lift adapters, Plugging in different outlets, everything.
So i plugged the (unbalanced 1/8") Line-Out out of my computer into the DI-Box IN. And i plugged balanced 1/8" to XLR from the DI-Out to my active monitors. I still have ground loop buzz when the harddrive works or i scroll the mouse. What can i try next?
I am getting AC Hum and Im not sure if this video helped. My setup * Laptop plugged into same AC powerstrip as Monitors * M-audio box (plugged into laptop via USB) * then 2 KRK monitors (RCA to 1/4" connector coming from M-Audio * Then my Mic is plugged into the M-audio box with the 48v turned on. I get a hum unless i touch the metal part of the XLR cables. As soon as I let go it comes back. Which device from this video could help me and where do I place it? Please help!
Just bought a new amp and power supply. Both devices were tested at the retail store and worked ok. However, having connected the amp and psu to ac power at home when i plug input cable or even touch one of the input terminals with my bare hands i get a deafening hum from the subwoofer. Also a problem i had ignored before even purchasing the amp and psu when i touch the bare audio input cable from a receiver I get shocked just a tiny bit. It seems like my AC is not earthed properly or something, I dont understand much about electrical engineering. How do i fix my problem?
Well, after watching this video among others, and reading a few long articles about eliminating ground loops, I am now more thoroughly confused and frustrated than ever. Thinking and hoping that I was now better informed and able to eliminate the AC hum from my system, I proceeded to reconnect the essential components only, after unplugging everything from my AC outlets. I don't have a studio, don't do any mixing or recording and only want to playback music so I went to plug in the three pieces that I believe are absolutely essential to do so, my cd player, preamplifier and powered monitor speakers. I would plug my CD player directly into my speakers, but I don't have compatible interconnects(the CD player has analog RCA line level outs while the monitor speakers have balanced XLR and TRS inputs) and believe the preamp is necessary anyway. All three have three prong grounded AC plugs. I wanted to plug all three into the same power outlet but unfortunately there are only two electrical "sockets" in the outlet so I added a 6 outlet swivel "side socket" into it, which is only connected to the wall outlet by a single three prong plug which I'm hoping is equivalent to using only a single outlet. I also have a power strip, but that also caused me problems and thought this arrangement would be better and more convenient. Anyway, I plugged in my CD player, preamp and powered monitor speaker and waited to see if the hum persisted, which it unfortunately did. The CD player is connected to the preamp using analog Red/White RCA line level interconnects, while the preamp is connected to the monitor speaker with a balanced XLR cable. After hearing the hum, I turned the CD player off and the hum level actually lowered slightly, then I unplugged it, but I don't think there was any significant difference between it being unplugged and powered off. What was much more significant was the preamp, it contributed a major amount to the humming sound coming out of the speaker. I unplugged the preamp and the humming sound diminished significantly, but not completely, there was still a very low amount of "static" emanating from the speaker. When I plugged the preamp back in, again it contributed greatly to the humming sound coming from the speaker, and when I plugged in the CD player and turned it on, it adding a little bit more buzz. I'm not sure if this is indeed a ground loop or if it is simply the ground noise level of my system, but either way, the hum is too loud to be tolerated by me and I shut it all off in frustration. Given that I only had the three essential components plugged in, what can I do to eliminate the humming sound to make my system usable? I suppose I'll have to buy one of those things mentioned in the video, but I'm reluctant to spend any money and more importantly, I don't have the right inputs/outputs(and I would rather not have to buy more/new interconnects) and honestly would not know where/how to install it in my system. Of course I am definitely not wanting to get a ground lifter plug until it is absolutely necessary which I don't believe it is after all the research I've done, nor am I the kind of person to cut the ground prong off of my plug. To make matters worse, there seem to be a myriad of ways of solving ground loop problems and I would want to use the best, most effective one, but also the most cost effective one as well as I am on a pretty tight budget right now. Any ideas/suggestions would be appreciated, thank you. And yes, I have watched this video(and others) all the way through, but honestly, I still don't really understand what's being said(it really is a very basic course in understanding electrical circuitry and stuff) and even if I did, there's a difference between theory and application. For example, there are a lot of people who can do math problems for homework by rote in a book, but haven't the slightest idea of how to apply it to real life situations(I"m not generally one of them, but the actual application of concepts is not always easy and certainly benefits from experience and repetition, something which I don't have the benefit of) Finally, believe me, I like understanding the theoretical aspects of a problem and knowing why I should do something, but at this point(being frustrated) I'm more practical and just want to fix the problem and get on with my life; I want to relax and listen to some good, tranquil and soothing music.
+mydogskips2 Hums and buzzes are not a simple thing to diagnose. There are just too many variables. If you are handy with a soldering iron you can try the "poor-mans" ground lift, Open up the pre-amp end of the XLR cable and locate the shield. It should be soldered into pin 1 of the XLR connector. Disconnect it from the pin 1 connection either by de-soldering or clipping it off. Plug things back in making sure the cable shield does not touch anything and see what happens. You don't have to be worried about shocks here since both chassis are (supposedly) grounded with a 3 prong plug and the signal level is 1 volt or less. You've got a 50/50 chance that it will help. If not, be sure to solder the shield back into the connector. If it does help, solder the shield back in place and by an isolation transformer. Doug
+Douglas Sebens Thanks, but I'm not at all handy with a soldering iron or anything else. I wouldn't feel comfortable opening up my preamp and I'm not sure which is pin 1 on my XLR cable. I do appreciate your interest and response however, and only lament my ignorance on the subject.
I get a lot of humming while using my phone through the mixer ,, what device ,, which way is the best way around .. which isolator is the best one to use .. (inexpensive
Audio cables and power cables should be loomed away from one another and if you still have a hum...you nd to replace a audio cable somewhere and finding it is easy by disconnecting one at a time.
one question. i have an europe type outlet in my house ( 2 holes ), not an uk one, with that 3 holes ish. so what cables can i use to connect my equip ( not to meny, 2 speakers and a piano , i wanna buy this because my hs 80m makes a white hmmssss noize when the volume it s around 12 a clock ). can/should i put a power pc desktop type cable from one outlet of the furman and then put a normal outlet to connect my 2 holes outlet ????? or can i simply plug a 2 hole stuff in that Furman 3 hole by clicking that third pin that opens the other 2.....???? hope i maade myself clear . Thank you.
This video is about to be 9 years old and still providing so much information. Thank you very much, sir.
11 now
@@winataatmaja3457😢
for a layman in audio engineering but an active musician, this is amazingly clear and understandable. thank you for the explanation
If only all teachers at school were this good.
I've been looking for a good explanation of ground hum for years. This video was very well done. Thank You.
I worked in the ROV industry. We sent control signals and video over umbilicals 1000 Meters or more in length. Ground loops and noise were serious issues as well as the risk of fatal electrical shocks. First we had our power supplied by an Ungrounded Delta Wired Generator. This eliminates a power return to ground making operations much safer for personnel and equipment and while this option really does not apply with sound equipment I supplied it to show sometimes the problems can be caused by normal safe practices.
We eliminated or mostly got rid of our ground loop problems by isolating chassis or electrical ground from any signal ground or signal path or return. In some systems we could have as many as four different isolated grounds. The bad news is that signal voltages could float above normal electrical ground but there was no path for current to flow. I would like to see the professional audio and sound operators and manufacturers adopt this philosophy by using totally isolated signal paths eliminating ground loops by doing so.
This video just helped me with a year long problem in my guitar setup. I had been chasing the problem, not getting results, and about ready to move out of my house because that had to be the problem thinking i had tried everything else. Thank you so very very very much. I added a studio monitor to my sound about a year ago and plugged it into an outlet on the other side of the room. Today I changed it to match where my amp is powered. Thank you so very much.
This video is so amazing. 30 plus years in as a gigging musician and I learned a lot. I will def buy something from you all.
Slightly above my head, but I got most of it. Thanks for putting this together.
A good video. In sound systems, howling, hum noise, ground noise, and oscillation (higher frequency instability) are big problems and each one has its own ways of being eliminated or attenuated. Oscillations sometimes have to do with amplifiers with very high feedback loops or with output and input lines to close to each other. Ground noise has to do with the so called ground loops while hum noise has to do with micro lines peaking up harmonics of line frequency that propagated by air or by AC lines to close to audio lines.
Howling has to do with microphone and loudspeaker closed to each other or resonances in the space where the system is used. To attenuate this trouble we have to reduce sound level, reposition micro and speakers, use frequency shifters and/or equalisers.
The PCB ground line is normally connected to the chassis somewhere and it is the main source of ground hum.This hum can be attenuated if we cut this direct connection (it is a short circuit) and connect both grounds through a wire wound resistor of about 10 Kohms having in parallel wit it a 2 MF ceramic, polyester, etc, capacitor.
Great explanation - best I have seen on this important topic for anyone working in audio engineering!
What a great video. My set up is as follows - Macbook, connected to a wall powered mixing desk via a USB insert - in that mixing desk I have an XLR condenser mic connected, using another wall powered compression unit, connected through an insert on the same channel as the mic. No problems, no ground loop. The problem began when I tried to do something very simple, which was add a 3.5mm TRS to Dual 1/4" TS cable between the mixer and my DSLR camera,, so that the mic runs through the camera (for better lip sync on live stream/conferencing). Instant ground loop and very loud hum and buzz and I couldn't work out why. Now I know why. I'm using my DSLR camera as a webcam, which is also wall powered with a dummy continous battery - when connected to the mixer, this means I have two different wall powered devices running through it (the compressor and camera) which is obviously causing the loop (with the USB connected wall powered Macbook which may or may not be adding fuel to the fire). I've ordered one of those decoupling boxes and will expect that this will work, when connected between the camera and mixing desk. Fingers crossed.
Very knowledgeable description of my buzz/hum. The solution might be beyond my budget. Thank you for sharing your expertise. Based upon your explanation I tested a couple things. Unplugged all devices, mouse, external hard drive from the usb ports and unplugged AC too.
When I move the AC cable close to its import connector or my computer the buzz grows. I'll have to record without it being plugged in.
Thanks again for your help.
Best video I've seen yet on this topic.
love your explanation, clear, crisp and correct.. as an electrical engineer, I appreciate the way you explain the balance signal with differentiate amp to eliminate noise while producing 2X the signal.. I'm hoping your next video is going to be about eliminating feedback with home entertaining system .. singing karaoke at home produced a lot of feedback, and I bought a few feedback destroyer devices, but none of them seem to help.. Thks..
Hi I know this video is a lil old but thank you so much for explaining this properly, you explained this better than my tutor
Thankyou for the info. It makes me crazy hearing that buzz. In my case it was Coming from a computer. You nailed it.
Wow... this is an ad and.. you are teaching us stuff... how cool is that?
I'd happily buy after this
Nice explanation.
This is exactly why a ground lift switch on DACs with an USB input is a very useful feature, but often overlooked.
thank you so much for making this video available. you would not BEE LIEVE what people at music stores do _not_ know.
very easy to understand with all the animations and clear voice. Thanks.
I loved this break down especially with the graphs. it helped a lot to understand what is 'actually' happening.
Nice algebraic explanation of balanced cables at 8:12!
Trying to figure out the hum in our church live stream setup, and this explanation helped a lot - thank you!
I was having this problem a few months ago with our PS3 when I connected it to one of our stereos. Tried using grounded adapters for the outlet plug like someone on a forum had recommended, but that didn't work. Figured out that the AV cable was sitting on top of the power cable from the unit. I simply cut a small 3" length of pipe insulation (which I already had) and placed the AV cable inside of it, then let it rest atop the power cable, instead. Hum immediately went away and hasn't been back. Wish I had thought to do that, first; would've saved me a few bucks on something I don't use. :)
May I ask what kind of pipe you used?
@@randinonsense7360 pipe insulation, it's a foam rubber sleeve like a pool noodle. I think it worked for him because it physically separated the two cables enough that the AV cable didn't pick up any EM radiation from the power cable.
this is my favorite video on youtube. thank you
Really appreciate this video. Was never a physics guy in school, but you made it all very easy to understand.
excellent video!! I live on 4th floor in a 120 year old block of flats in Madrid. The 240 juice fluctuates on a daily basis . i dont think the earth cables get all the way to the bottom!!
Thiis presentation was very informative . THANKS
After 10 or so hours of trouble shooting/investigating/self educating, this video made everything clear.
We're going to take an old set of balanced trs cables and remove the ground pin on the trs connectors on the monitor ends.
This will be our ground lift point for the two monitors.
Configuration we have is computer tower - usb to interface - interface output via 1/4 inch trs to each monitor. Each monitor is self powered/grounded, so we have a ground loop between the monitors via the interface. Ground lift on the trs cables on the monitor ends should fix our hum/hiss/pops
Best explanation I've found on youtube!
Thanks for the "balanced input". it was very well "received".
Excellent presentation + clearest explanations. --- I have never found an explanation for similar problems in a 2 wire (AC) 220V European circuits, though. Are those boxes identical in construction and use? Is AC filtering done the same way, since they don't have 3d prong for ground? I thing that Alectro is the place to get answers and... to shop. Bravo!
Cutting signal wire ground could introduce RF noise due to antenna effects.
However, these effects are (almost) non-existent in audio systems due to the cable and wavelength. Unless the system is >6km (λ/f)
Cutting the signal ground but leaving the shield intact is the safest budget solution.
Great explanation of ground loops.
Just being picky here but when you say '180 degrees out of phase' you are actually talking about opposite polarity. Phase implies a time delay, having the same signal just delayed half a cycle. Your statements get the point across but to be accurate you should use polarity.
Yes, opposite polarity. In-phase would imply exactly 180 (degrees) of phase, anything other than 180 (degrees) are referred to as "out of phase." Phase does not imply a time delay. If you calculate it 2 phases (1 cycle) at 60hz (60 cycles or 120 Alternating polarities a second. But your ear wouldn't hear this as a delay. Phase refers to a relationship between positive and negative polarity in the sine signal. As it pertains to microphones and pick-ups, out of phase would imply an auditory delay not a delay from a ground loop.
Indeed Douglas Sebens, it is a common misconception. It is not 180 degrees out of phase, it is inverted.
However, the ground loop explanation is fundamentally wrong in this video, so not so great.. There is no potential difference between the earthing connections of wall outlets if no devices are connected to them. Once a ground loop is created (or any loop of electrically conducting material), a current starts to flow through the loop, creating the potential difference.
And by the way, jon wilson, you're talking shit.. it makes no sense at all.
A lot of great tutorials. I have an issue that two “Professionals” could not fix. Do you make house calls?
I used to work on sound systems for churches and my own church drove me insane with hum. Had to do many crazy things to get it down and quiet. What do you have going on???
Massive thank you, very clear and solved the issue in a matter of seconds...
Excellent video, thank you. Wish I had this knowledge years ago.
Actually, this video helped me tangentially. It prompted me to look at the many connections in my modest shack and reconnect some of the AC feeds. This provided a modest improvement, so it seems that I am on the right track. It's still humming, since I couldn't pull the rascal out of the multi-tap feed. It's funny though, the problem of humming just suddenly appeared. It's freezing here ... nothing works ... time to call Ghostbusters.
Very good and detailed explanation. Super helpful, thank you!!
Thanks for this tutorial has help me to understand how I should set my system up and what type of speakers leads I need use or devices to accompany as an option.
Wonderful explanation. Clear video .
I've gone through the content along with conceivable way of explanation on subject & pattern of elaboration of issues & there causes & solutions. Big thanks for the same!!!
It would more useful , if available in Hindi (Hinglish) language retaining of technical terms in English!!
Thanks ! That video was very basic, but very useful !
I solved my hum. I used two channels of my Mixer/Amp, plugged the left and right RCA cords from my laptop into separate RCA to 1/4 inch phono jacks, one in each channel.
At 14:05, if the laptop's input is stereo (unbalanced) and I'll send signal to it from an unbalanced aux-send, how would you make the connection balanced? Thanks!
thank you very much for this video. i'm wondering if the DI box capabilities of audio interfaces can suffice or should a separate DI box be used because i still get nasty hum out of my electric guitar when i connect it to my audio interface to my laptop.
Amazing, thanks for lecture. So useful. Best found so far.
If a laptop has a ground loop, just unplug it from the wall and use battery. Also, there are other such transformers to break ground loops from Whirlwind, Radial, etc.
Thank you so much sir for your packaged information.
this video put me onto the right track to resolving my sound issues. my desktop had a major hiss, my laptop on battery power did not. thank you so much for this very informative video.
This sounds familiar. We had a problem for a while in our rehearsal space where I would get shocked if I touched my guitar strings and the cage of an SM58 at the same time. I assumed it was a ground loop between the mixer and my amp, so I just started mixing and matching outlets throughout the room, and found that as long as my amp was on the same power strip as the mixer, I could plug my pedal board (about 6 analog pedals daisy chained on a 9 volt power supply) into an outlet on a different breaker and avoid getting shocked.
So I'm not sure exactly where the loop was, but I broke it somehow!
i was looking into ferrite noise filters or maybe toroids, is that the main ingredient in some of these boxes? toroids can be expensive it looks like.
Thanks very much for the explanation. I have a few questions as follow:
1. If possible, please explain more of the differences between passive DI box and Active DI Box, which one is better and why?
2. I noticed at both active and passive DI box settings there is a button call GROUND LIFT, which one should we choose ("GND" or "Lift") in order to eliminate the ground loop noise?
3. In the DI box, may I know what is that "Attenuator/Attenuation" all about? And which setting should we choose (i.e. 0, -20 or -40?)
3. Can I simply use DI box for all ground loop problems instead of AGDC2? (because in my location I see only DI box available in all the music shops, never seen one like the AGDC2, never even heard it before.)
I have the Shure Wireless MIcs using XLR cable to connected BMB karaoke mixer input. It works fine, but want to add the compressor of BEHRINGER MULTICOM PRO-XL MDX4600. After connect them all together. IT have the hum sounds. So I think I need the DI box? if so, do I need just 1 DI box or 2 boxes since I currently have 2 mics? Thx
Thankyou for this amazing video
This video is a Godsend
Wonderful explanation
Thank you so much! Your video helped me a lot.
So, my chain looks like this: guitar->usb audio interface -> pc(running guitar rig/bias/etc). In this case there is a lot of hum,but some noisegates can handle with it, but when i add a preamp beetween guitar and audio interface no gate can help.
Now,the question is - if it's the groundloop conflict and if a dibox may help solving this issue?
Many thanks anyways
I have mains hum probably due to a ground loop between hi end hifi components connected to the same outlet.
None of them have balanced inputs or outputs. If I used the unit you recommend surely it means I have to use more interconnects and wouldn’t it interfere with the purity of the sound in such a system?
My DAC and transport are from China. Is there a chance this affects the situation in any way, by having slightly different voltages?
thanks for making this! no more humming...
I have a balanced xlr that goes from a preamp pedal and into my computers soundcard which has a 3.5mm input. My question is....are line ins on soundcard balanced....unbalanced....or capable of handling either? Reason I ask is I have ridiculous noise and I'm trying to narrow down exactly where the issue is....without buying yet more things that ultimately have no or little improvement. I'm thinking a 3.5mm in line ground loop isolator might be the key....but I'm not certain.
....thanx ....reinforced my understanding of ground loops and ac hum...
Wow this was very helpful
Great video! I'm a street performer and I face humming when I plug my amp (battery powered) and my pedals (which run through a power bank), if I swap my eletric system for a car battery powering everything, would the humming quit?
Yes.
But you would need to make sure about power consumption of both of those systems, as a sudden peak in each one would hinder the working of another one.
I understand very well thanks for your help.
DI boxes will operate with any signal level from guitar up to loudspeaker terminals, thanks to attenuators.
very educative. Thank you regards
Hi, great video great explanation, subbed.
I'm having a problem with my rig and beg for your help to understand what's the cause.
I plug my guitar (Ibanez RG with two Humbuckers and one single coil, properly grounded and shielded) straight to my Line 6 POD HD500x (wich is powered by a two pins plug transformer (I'm in Europe, so, no ground connection) and then monitor it through headphones. I'm getting a 50 cycle hum that goes away when I touch metal parts of guitar or POD.
What's the cause of the hum? Lack of ground connection to the wall socket?
although it is most likely your line 6, check if you're plugging the headphones to the designated output. If you're plugging it to the line out, or the main out that goes to your amp, that might be the issue. also, the line 6 has a ground connection, which you can plug some wire into or touch with a screwdriver. If none of this works, get a grounded plug. Because we have grounded plugs in Europe too.
your guitar ground is good? is your guitar cable good quality? like does it pick up sounds?
I have a question, and I have no knowledge on AV, so I’ll try to explain my question the best I can, but at my church We upload the sermons live to Facebook, the audio for the video is what is coming from the board(not a separate mic) and there is a hum in the video audio, so how do I know if I need a 2 channel line level decoupled or a DI box?
I have an the same problem
Great video! Do voltage regulators help? My system also has a hum but only Ribbon Microphones bring it out clearly. As you described in the video, my 50ft. snake amplifies the hum signal very well. So I wonder if I plug all my equipment into a single Voltage regulator such as the APC LE1200, would that get rid of the hum?
+OZ B Just realized that I may need a Power Conditioner - not a regulator! Going to try the Furman M-8X2. Anyone else try that unit to eliminate hum and hiss?
i kept watching because of your voice 0_0
I literally just told my husband how much I love his voice. I would love to hear him read in every audio book.
What if I only have one device in the socket with no other devies interfering with it, but still get a ground loop buzz? The buzz also only happens with one guitar amp and not with others.
I've a turntable and an hi-fi both without earthing to wall.
Other source devices are connected to the same wall power strip, noone with earthing.
The grounding between these devices is linked through the unbalanced L+R phono cable with the earth thiny wire.
Noise is present and follow the volume level. But still present if the turntable is disconnected from cable.
With same speaker I've also tried two different hi-fi system. I can't figure out how the problem can be generated by AC and how any DI Box can be help in this scenario..?
Thanks for a really great video!
This is so perfect.. Thanks a lot to make it such simple....
Ground links should always be considered because of their uniqueness to the spere magnetism system...The audio line and ohm link is imperitive to understand.
So, I currently have an odd setup, so perhaps you can let me know a better way to deal with it. I have 2 different dacs feeding two different audio sources, when either is used individually, the ground noise is essentially zero, but when the two sources are merged, there is a horrible buzz. The signal is sent stereo via 3 wire, and I assume the problem is the shared 0v ground aren't the same on the two sources. One of the dacs is grounded to earth, but the other takes DC in and isn't ground referenced at all, i assume it functions on virtual ground. How would I mix together these two sources without the grounds clashing then causing hum?
Basically, I am attempting to have two different audio sources play on the same set of speakers, without buzzing occurring when more than one source is hooked up at the same time. Currently my solution is use a 2 way toggle switch that I have to flip manually to switch between the sources grounds, but I hate this solution.
Is this normal to happen if you plug studio monitors directly into the wall? Would this be an issue within wiring within my house and could a power conditioner help here?
Hi, if I connect the guitar amp with a trs balanced cable into the console need a direct box?
I get crackle sounds from just 1 speaker in my home theater since I added a 7ch amp. I can't seam to solve the issue. What should I do? Some told me to buy a conditioner. The amp and receiver are connected with unbalanced rca as the receiver doesn't have balanced xlr's. I also have the amp connected in a different outlet because when the amp was on the same outlet it was shutting off du to possible line sag.
My home theatre hums as soon as I turn it on regardless of if it's connected to anything else. I'm even using optical cable, so this should not effect it anyway. Do I just have a crappy speaker?
I still don't know how to make my amp quit humming.
Gerald Ritchey Are the cables balanced going to your amp? What does your set up look like. I may be able to help you. Don't cut anything.
Roger Stevens It's a brand new Ibanez bass and a brand new Mark Bass amp. I bring it to my house and plug it up; no hum. I take it to where I play it, plug it up; constant hum. I've tried ground lift adapters, Plugging in different outlets, everything.
Gerald Ritchey Make sure there is no transformers near your amp and output device.
What if you use a two-prong to three-prong adapter?
John Kennedy need help also my VIDEOKE machine also has a nosie sound when I turn on my microphone it started to humming.
Very informative! Thanks!
So i plugged the (unbalanced 1/8") Line-Out out of my computer into the DI-Box IN. And i plugged balanced 1/8" to XLR from the DI-Out to my active monitors. I still have ground loop buzz when the harddrive works or i scroll the mouse. What can i try next?
Very good video!!! thanks
Really helpful, many thanks.
very educational! Thanks!
Passive DI boxes (transformer type) can be used "backwards" to convert balanced back to unbalanced
I am getting AC Hum and Im not sure if this video helped.
My setup
* Laptop plugged into same AC powerstrip as Monitors
* M-audio box (plugged into laptop via USB)
* then 2 KRK monitors (RCA to 1/4" connector coming from M-Audio
* Then my Mic is plugged into the M-audio box with the 48v turned on.
I get a hum unless i touch the metal part of the XLR cables. As soon as I let go it comes back. Which device from this video could help me and where do I place it?
Please help!
Just bought a new amp and power supply. Both devices were tested at the retail store and worked ok. However, having connected the amp and psu to ac power at home when i plug input cable or even touch one of the input terminals with my bare hands i get a deafening hum from the subwoofer. Also a problem i had ignored before even purchasing the amp and psu when i touch the bare audio input cable from a receiver I get shocked just a tiny bit. It seems like my AC is not earthed properly or something, I dont understand much about electrical engineering. How do i fix my problem?
I just use two cheap diodes and a loopbucker resistor to break ground-loop.
Cheers from Indonesia
innovative information thank u for the videos
Any idea for hum caused by connecting a laptop to USB Audio Interface which supplies phantom power to a condenser mic
I've always had this problem with my Yeti USB mic. 2 years later, did you ever happen to find a fix?
Well, after watching this video among others, and reading a few long articles about eliminating ground loops, I am now more thoroughly confused and frustrated than ever.
Thinking and hoping that I was now better informed and able to eliminate the AC hum from my system, I proceeded to reconnect the essential components only, after unplugging everything from my AC outlets.
I don't have a studio, don't do any mixing or recording and only want to playback music so I went to plug in the three pieces that I believe are absolutely essential to do so, my cd player, preamplifier and powered monitor speakers. I would plug my CD player directly into my speakers, but I don't have compatible interconnects(the CD player has analog RCA line level outs while the monitor speakers have balanced XLR and TRS inputs) and believe the preamp is necessary anyway. All three have three prong grounded AC plugs.
I wanted to plug all three into the same power outlet but unfortunately there are only two electrical "sockets" in the outlet so I added a 6 outlet swivel "side socket" into it, which is only connected to the wall outlet by a single three prong plug which I'm hoping is equivalent to using only a single outlet. I also have a power strip, but that also caused me problems and thought this arrangement would be better and more convenient.
Anyway, I plugged in my CD player, preamp and powered monitor speaker and waited to see if the hum persisted, which it unfortunately did. The CD player is connected to the preamp using analog Red/White RCA line level interconnects, while the preamp is connected to the monitor speaker with a balanced XLR cable.
After hearing the hum, I turned the CD player off and the hum level actually lowered slightly, then I unplugged it, but I don't think there was any significant difference between it being unplugged and powered off.
What was much more significant was the preamp, it contributed a major amount to the humming sound coming out of the speaker. I unplugged the preamp and the humming sound diminished significantly, but not completely, there was still a very low amount of "static" emanating from the speaker. When I plugged the preamp back in, again it contributed greatly to the humming sound coming from the speaker, and when I plugged in the CD player and turned it on, it adding a little bit more buzz.
I'm not sure if this is indeed a ground loop or if it is simply the ground noise level of my system, but either way, the hum is too loud to be tolerated by me and I shut it all off in frustration.
Given that I only had the three essential components plugged in, what can I do to eliminate the humming sound to make my system usable?
I suppose I'll have to buy one of those things mentioned in the video, but I'm reluctant to spend any money and more importantly, I don't have the right inputs/outputs(and I would rather not have to buy more/new interconnects) and honestly would not know where/how to install it in my system.
Of course I am definitely not wanting to get a ground lifter plug until it is absolutely necessary which I don't believe it is after all the research I've done, nor am I the kind of person to cut the ground prong off of my plug.
To make matters worse, there seem to be a myriad of ways of solving ground loop problems and I would want to use the best, most effective one, but also the most cost effective one as well as I am on a pretty tight budget right now.
Any ideas/suggestions would be appreciated, thank you.
And yes, I have watched this video(and others) all the way through, but honestly, I still don't really understand what's being said(it really is a very basic course in understanding electrical circuitry and stuff) and even if I did, there's a difference between theory and application. For example, there are a lot of people who can do math problems for homework by rote in a book, but haven't the slightest idea of how to apply it to real life situations(I"m not generally one of them, but the actual application of concepts is not always easy and certainly benefits from experience and repetition, something which I don't have the benefit of)
Finally, believe me, I like understanding the theoretical aspects of a problem and knowing why I should do something, but at this point(being frustrated) I'm more practical and just want to fix the problem and get on with my life; I want to relax and listen to some good, tranquil and soothing music.
+mydogskips2 Hums and buzzes are not a simple thing to diagnose. There are just too many variables. If you are handy with a soldering iron you can try the "poor-mans" ground lift, Open up the pre-amp end of the XLR cable and locate the shield. It should be soldered into pin 1 of the XLR connector. Disconnect it from the pin 1 connection either by de-soldering or clipping it off. Plug things back in making sure the cable shield does not touch anything and see what happens. You don't have to be worried about shocks here since both chassis are (supposedly) grounded with a 3 prong plug and the signal level is 1 volt or less.
You've got a 50/50 chance that it will help. If not, be sure to solder the shield back into the connector. If it does help, solder the shield back in place and by an isolation transformer.
Doug
+Douglas Sebens Thanks, but I'm not at all handy with a soldering iron or anything else. I wouldn't feel comfortable opening up my preamp and I'm not sure which is pin 1 on my XLR cable.
I do appreciate your interest and response however, and only lament my ignorance on the subject.
I get a lot of humming while using my phone through the mixer ,, what device ,, which way is the best way around .. which isolator is the best one to use .. (inexpensive
Audio cables and power cables should be loomed away from one another and if you still have a hum...you nd to replace a audio cable somewhere and finding it is easy by disconnecting one at a time.
What if I live in an old building in Denmark that has no ground at all on any of the outlets in the apartment?
at 12:09 i'm confused, what is the source audio for the agdc2?
Signal coming from mixer into agdc2 into the speakers. The source could be anything (mic/instrument/...) connected to the mixer.
Wouldn't the decoupler be better with XLR connectors? Just asking...
one question. i have an europe type outlet in my house ( 2 holes ), not an uk one, with that 3 holes ish. so what cables can i use to connect my equip ( not to meny, 2 speakers and a piano , i wanna buy this because my hs 80m makes a white hmmssss noize when the volume it s around 12 a clock ). can/should i put a power pc desktop type cable from one outlet of the furman and then put a normal outlet to connect my 2 holes outlet ????? or can i simply plug a 2 hole stuff in that Furman 3 hole by clicking that third pin that opens the other 2.....???? hope i maade myself clear . Thank you.
Watch a video about correct gain staging.
Please I want you to show me how to connect combo speaker to a mixer to serve as monitor speaker