Ground Loops: What Are They and How to Eliminate Them in Audio Rigs

[@CarsSimplified]

I got an ad on a completely different platform for an article on this subject. I hadn't heard of it before, so now I'm here instead of going to that article that was probably trying to sell something. Great video!

[@RecordingLounge]

I hope it was helpful! And hey, good news is that most of the time these things can be fixed without spending any money. Other than the need for isolation transformers Sometimes!

[@chrismillett]

Very easy to understand! Thanks Kendall 🤘🏻🤘🏻

[@userfriendlysounds]

Thank you so much. Excellent explanation and information as always.

[@jazzman9469]

Great advice, thank you. Here is my problem; I have Klipsch 2.1 computer speakers. When I plug the green end cable into the motherboard, there is a loud noise and even if I just slightly move the cable it is sooo loud. Also to that, when I mouse over (not click) a link, there is a pulsing noise coming from the speakers. Talk about annoying. I used these speakers on my old computer and no issues. Now on my new computer with a Gigabyte motherboard, there is. Old computer, Windows 10, new computer, Windows 11 if that helps? Thank you.

[@MrCloudss]

I have a similar hum noise when I connect my guitar cable to my amp. I just have one power supply going to the outlet for the amp. And my guitar is directly plugged to the amp with nothing in between. I don’t think a loop is formed in my case. But I still get the loud hum noise when I connect by guitar cable(even when my guitar isn’t plugged in) But when I do connect my guitar the noise is still there but when I touch on my guitar body or guitar strings the noise gets lower. What do you think my issue is? Thank you on advance.

[@shapourdashtpour63]

Hi, I am upstairs. In one outlet I have two power strips connected. In the other outlet I have a guitar pedal connected. Anytime a specific downstair room turns on the light, I will get a buzz in my Amp. Do you think I should get Behringer MicroHD HD400 2-channel Hum Destroyer Or Morley Hum Exterminator Ground Loop Hum Exterminator Or Furman M-8x2 8 Outlet Power Conditioner Thanks

[@dylanjohnson7882]

Excellent video, thank you! Can you help me understand how it's still possible to have a ground loop in your examples where all equipment is plugged into a single power strip/the same socket?

[@RecordingLounge]

Yes - so ground loops can form any time two [interconnected] pieces of equipment have different paths to ground, each having slightly different ground voltages or resistances. So if two pieces of gear both plugged in but are interconnected by an AUDIO ground (let’s say one is a pre and one is a compressor) it forms a loop: piece 1 goes to the outlet, and connects to piece 2 with an xlr cable (which has a ground) and piece 2 also goes to the outlet. Hence your loop. Current can flow around this loop from outlet > piece 1 > audio ground > piece 2 > outlet and back again.

[@RecordingLounge]

If the two pieces of gear aren’t interconnected, you won’t form the loop. like say it’s two guitar amps but one is played by Guitarist 1 and the other is played by guitarist 2. There will be no loop because the two amps are not interconnected with an audio ground. But if guitarist 1 uses a splitter and goes to both amps, you form a loop from splitter > amp 1 > outlet > amp 2 > back to splitter

[@marcusstrymon693]

So reamping without a reamp box into lets say pedal reverbs and then back to the interface creates a ground loop, correct?

[@RecordingLounge]

It can. That’s one reason why most reamp boxes have transformers and ground lifts. But, the transformer is also there to convert the impedance from low to high, and to convert balanced to unbalanced. And Like I said in one of my other comments, ground loops are kind of everywhere in complicated setups. Often, they are very noisy. Sometimes they are not.

[@RecordingLounge]

Also remember… if the reamp box is passive, and the pro audio gear has a well designed power supply, then they’re both isolated from the power side of things.

[@marcusstrymon693]

So what I dont get: I would have to put a DI box between any rack unit, right? I go XLR out from Rack eq to rack comp, voth use piwer cable --> ground loop I go rack chanel strip --> interface, both have power --> ground loop

[@RecordingLounge]

So, I know exactly what you’re thinking - and yes on paper it does look that way. But frankly, balanced pro audio gear does such a good job at rejecting noise and isolating in the power section that this is basically never an issue. For years, a standard way to wire studios was “OEO” aka “one end only” meaning, one side of the balanced line had a ground lift, exactly for this reason. Every single piece “theoretically” creates multiple ground loop since they are all connected to power, audio, AND they’re all physically touching in the rack rails! But truth be told, ground loop noise is a spectrum, meaning, there are “worse” ground loops than others. Some are insanely noisy. Some are technically ground loops but don’t have bad noise, as is the case in 99% of rack gear. The amount of noise is based on the small voltage differences, and for balanced pro audio it’s just not that bad. Imperceptible in most cases. So most studios don’t even bother with OEO wiring anymore, and most gear manufacturers are hip to this nowadays and design their gear well to accommodate for standardized wiring.

[@RecordingLounge]

When you first “get it” it’s easy to look around at all of your gear horrified and be like “oh my god it’s all ground loops!” lol but don’t fret. Fix the noise when it’s a problem. If it’s not a problem, then no need to fix or change anything. And thankfully most gear nowadays is well designed enough to not have these problems. But like, I have to use a ground lifted setup on my vintage LA3A because it has a ground loop problem when interconnecting to other gear. But that piece is like, 60 years old.

[@marcusstrymon693]

What if I use 2 isolated power suplies? In my case a voodo lab pedal power 2 and a styrmon ojai? Still a problem? So I have a ground loop somewhere in my board. For the last 8 pedals its all hood (all strymon pedals) but then it doesnt matter which other brand pedal i add, I get hum and rumble (low level) i have changed the strymon order afterwards and changed the cables so none of the strymons is at fault. And I have added the other pedals to the "good" ojai power. Doesnt mattr which one i add, the boss eq, jam pedals drives, expression pedal. A bit of buzz is there regardless. Does this just show the good build quality of strmon or is something incredibly off?

[@RecordingLounge]

Well, Strymon pedals and power supplies ARE really well designed, are super quiet, and have excellent power isolation. And yeah there potentially could be issues using two different power supplies but, I don’t know, maybe not. That’s hard to say for sure and hard to diagnose. I’m not really sure I can say one way or the other just from this info. I would keep experimenting, try to rule out variables, different combinations. Make sure to test all your cables too. I’m sure you will find the solution. Sorry if that’s not much of a help.

[@marcusstrymon693]

@@RecordingLounge Mate thank you so so much for all your answers! This is really really interesting to me, like its kust fascinating. And truth be told, I really need to turm up level to hear the ground loop, like I mean Inneed to go into a rack unit and go balanced out, crank the gain on the interface and turn up speakers tonhear the geound noise (which then you hear clearly) But alsonthen white noise from the focusrite scarlett 18i20 is allready a lot louder (which is an issue) A little side note also: would you say that most pieces of analog gear could potentially add white noise? Bc yesterday I was recording the level of my signal chain white noise a) with the presonus studio channel rack unit b) without it (firstly recorded a looped signal to make sure the base level is the same for both) Sadly the rms for whote noise only was about 2.5 db louder for the preamped signal compared to the normal instrument level signal with the exact same signal level for the loop itself which makes me sceptical if more hardware units is even a good idea. Simce clean signal is king. Again, amazingly, 8 strymon units didnt add anything in noise, like they are stone quiet. They need to get into rack units more

[@RecordingLounge]

@marcusstrymon693 yeah, unfortunately white noise / hiss is normal for virtually ANY analog circuitry with amplification stages. It comes from transistors, tubes, even resistors! It’s unavoidable to some degree. I mean “Johnson noise” is literally the noise from electrons moving around inside of the components. Nothing can get rid of that. Over the years the components get better and the circuits get better. When it comes to analog gear you def gotta be careful with gain staging to keep it as quiet as possible. And keep in mind .. Strymon is primarily digital processing. They use the same SHARC chips that UAD cards use. There’s pretty minimal “analog” circuitry in there which is one reason they’re so quiet. And yeah, analog gear is noisy. Digital signal path with a clean pre can sit around -90, -95, 100dBFS. Insanely quiet. But a real Neve 1073 into an 1176? You’re sitting -70, -80 easy. Easily 20-30dB more than a digital piece. Some of it is just the cost of the sound. If you gain stage it right, the noise isn’t really much of an issue. But for some folks, they don’t wanna deal with it, or the sound of the dope analog stuff isn’t worth it for the noise. It’s something you get used to and learn to manage. It becomes part of the toolkit just like anything else - like, if I’ve got a quiet acoustic guitar player, I maybe can’t use that tube mic or compressor, because the noise is possibly gonna be too high. Maybe it’ll be worth it. But I might go for a solid state mic with a slightly cleaner pre and no compressor, and call it a good compromise. And when all else fails… there’s tons of great noise reduction plugins like Izotope RX. And sometimes that’s the compromise. We use the signal chain that sounds amazing but has a little noise, and just deal with it in post.

[@marcusstrymon693]

@@RecordingLounge thanks once again for the long answer, starting to understand things So essentially one could think woth strymon allmost plugin in a box, right? So the presonus that I use has noise floor of 96 db which seems okay, however its still anoying as an always on. It just gets progressively worse when using the comp and adjusting makeup gain (obviously). Still, the value seems okay ish compared to other units (Warm audio bus comp

[@ralphmcguire7668]

🔥 P R O M O S M

[@TubeTapeGecko]

Hey I’m using one amp, pedalboard powered by cioks both plugged into a power conditioner and humbuckers and I will get wild hum all the time. What do you think I should try?

[@RecordingLounge]

I would start by trying to narrow it down first: Try plugging straight into the amp, no pedals. Still get bad hum? If so, you could have a bad ground in your guitar. Try a different guitar. Same noise? A failing filter capacitor or bad connection within the amp can also cause hum. Try a different amp. If your guitar to amp is quiet, then add in your pedalboard. Could be a bad power supply (I’ve not had great luck with Cioks tbh), or a bad cable (extremely common) or a bad connection on a pedal jack (also common). The more you can narrow it down, the easier it will be to find the true cause of the issue. Also… make sure to quadruple check your instrument cables / speaker cables and make sure they are indeed the proper type, and that they’re wired correctly. Like I said, eliminate possibilities one by one. It can be time consuming, but it’ll be worth it when you actually find the root cause.

[@RecordingLounge]

Also I should say… if you turn your guitar volume down and you don’t have noise, there’s either a wiring issue, or more likely, there’s noise in the room being induced into the pickups. One of the only ways to solve that is distance: don’t sit too close to your amp or anything with a power transformer, any computers, keep your phone out of your pocket. Theres tons of devices around us all the time, and not even humbuckers are fully immune. Induced noise sucks. I wish we could do more about it.

[@TubeTapeGecko]

@@RecordingLounge I honestly think it might be my house because I still get hum plugged straight in. I’ve tried different guitars/amps and power supplies etc. would running a Lehle or something similar even with just one amp help at all or would that not work in this case at all?