After a lot of research, I settled on this approach and it definitely works. I read about the principles elsewhere, but came to the video to see a visual demonstration. I've suffered ground loop problems for 10 years(!) with unbalanced sources connected to balanced inputs on my active monitors, which need to be plugged in to different wall sockets due to the layout of the room. There are other recommended fixes out there, including lifting the ground pin on the power cable (dangerous) and spending money on isolators (can degrade sound, unless you spend a ton) hum removers, DI boxes, etc. This was my preferred option. I wanted a non-destructive method in case it didn't resolve the humming or I got too much unwanted interference, so I de-soldered the cable from pin 1 and folded it back against the sheath. Thanks for the video.
Thank you for the comment. Most of the time, the boxes that are sold to stop the "humming" are targeted for line noise and other "internal" noise producers, not for ground-loop situations. Having several ground-loop cables on hand will eliminate nearly all ground-loop situations. The idea is to know if what you are hearing is from a ground loop, or from something internal.
Chucking in the obligatory reply - NEVER TAKE THE EARTH OUT OF A POWER SUPPLY, EVER. Someone at my university died doing that the year before I got there. Scary stuff. (Sounds like you knew all this already 😅 just for anyone else reading...)
I'm surprised there aren't many videos talking about this issue... In my basement home studio, I have a mixer plugged into an outlet, and a Mackie powered speaker in another outlet at the other end of the room... i'm getting a bad ground loop, looking forward testing this out. Thanks!
I’m having this issue with my preamp which has a separate power supply with a buzzing transformer that you can hear. The transformer hum is making its way into the audio path via the line input when sending audio from the computer into the line and back. The mic or DI are fine. Any idea if this ground lift cable would be worth a try?
Looks like you are using home audio equipment...? I'm not sure about home audio gear. Though, if all your gear (including the preamp) are connected to the same circuit, and there is still a humming sound, this could be an issue with a transformer or something else (another noisy transformer) on the same circuit (refrigerator, florescent lights, etc...). However, sometimes humming/buzzing can be the result of an impedance mismatch between components. An actual humming sound is most always a ground-loop; whereas a buzzing sound is most always an issue with a piece of equipment. From what you described, a ground-lift cable may not correct the issue. When we connect computers/MP3/iPads/etc... into our system, we use a passive transformer that converts the impedance (of the device connected) to match what the sound system is expecting to see.
tried this just now. no safety or damage issues. it works fine. however, if you are using any xlr adapters (i.e. the triton fethead) which use all 3 pins, they will no longer be compatible with this modified cable. ecommended to try out on a spare xlr cable, but dont do it on the only one you have.
Hello there, great video! Just a quick question. I'm creating my own passive splitter snake (something like the seismic audio one). Should I be worried about this and cut the pins 1 on all of the connectors just in case? Two of my microphones are condenser, wouldn't that affect phantom power? And also our guitarist uses active DI where phantom power needs to be provided as well. I'm curious if I should cut the pins 1 just in case or you advise to have couple of lifted cables made aside. Thanks a lot, liked and subscribed!
Thanks for your comment. Good question. I would NOT cut the pins on any of the connectors on the splitter. Instead, (just as you said), pick up several short XLR cables and cut the pins in those... then use those cables on problem inputs only. I have about a dozen 1 ft. long cables that are ground-lifted. Also, if you are using a speaker management system (like the dbx 260), some of those units have built-in ground-lift switches on the rear of the units (usually next to the inputs). For most of the shows we do, I use the built-in ground-lift on our dr-260. I occasionally will need to use a ground-lift cable on the monitor signals (at the monitor console). For the DI's, many of those should have a ground-lift switch on them already (ground-lift switches are somewhat now normal on many DIs). If the DI does not have a ground-lift, just use a short ground-lifted cable on it. Phantom power should still pass with a ground-lift activated.
@@stageleftaudio Thank you so much for your reply! I'm basically building the split snake for the band where we use Soundcraft Ui24R as our IEM mixer and I'm not aware if there are any options to ground lift individual channel. With your experience what would you say is the most susceptible input type for ground humm? Dynamic mics, condenser mics, DI boxes, DI outputs from bass amp or the PA speakers? It's 3 of us in a band, acoustic guitar, bass, drums and all 3 of us sing, so I'm just curious how many of those ground-lifted cables should I make. If we use complete mic setup it's cca 14 inputs so should I have 14 short ground-lifted cables on hand? Can it happen on all of the inputs at once? Any info will be appreciated, thanks a lot!
Thanks for your setup information. This may be more information than what you need for your type of setup, but hopefully it will give you a broader picture of how ground-loops (hum) occur in a sound system. Hopefully it may help you decide how to handle a potential hum. The ground-loop in a system is not caused by the type of microphone or DI boxes used (unless there is something internally wrong with them). Though, the outputs on guitar and bass amps (including the built-in DIs on these amps) are sometimes prone to signal grounding issues, which can cause hum. Most all of the hum (ground loop) you hear in a sound system is caused by a continuous balanced (XLR) signal path between two different power sources. Pin #1 in an XLR cable (the ground) provides the only signal path that can traverse an entire system. When Pin #1 is connected (through all the grounds in a system), it creates a large physical loop (which generates interference) between at least two different power sources. For example, a power source could be at the FOH mixing location (for the console), and another power source could be at the stage (for the main PA, instruments, monitors, etc...). The FOH and stage locations would be connected (through a signal) using a multi-core snake; of which the snake would have many pin #1 connections. Removing the connection on pin #1 (as shown in the video) for the main output of the console breaks the ground-loop circuit between the two locations, therefore eliminating the hum. This also applies to monitor sends (if mixing monitors from FOH). Sometimes, it doesn't matter where the break occurs in the loop, just as long as there is a break. But also, not every setup has a ground-loop problem! The other issue that can cause hum (not related to ground-loops) is from some older instrument (mostly guitar) amplifiers that have wiring or other modification issues inside the instrument amp. The hum produced by these older amps gets amplified. Using a ground-lift cable on these types of amps will not correct the hum. Any hum from these older amps usually indicates it needs something fixed internally. It is possible to have multiple ground-loops in a sound system. Some of the ground loops can be localized to the stage from using multiple stage circuits when using multiple FOH amplifiers (i.e. sending the same FOH signal to many amplifiers). A ground loop (hum) can occur between amplifiers. Using a ground-lift XLR cable (as in the video) between amplifiers can eliminate the hum. You should only need a few ground-lift cables at most. In my large sound system, I may occasionally only need two ground-lift cables, and that would be used in the sending of monitor signals from the FOH console to a monitor amps. As well, all of my DI boxes have ground-lifts on them that I can activate or de-activate as needed for any instrument amp. IMPORTANT: Tracking down ground-loops (hum) in a sound system can take some time and may require good trouble-shooting skills. Ground-loops localized to the stage are harder to track down than those for FOH. Some instrument amps have XLR ground-lifts incorporated in them (usually at the output)... use those first before inserting any ground-lift cable. You should not use ground-lift cables on every input, because it can introduce a lot of noise into the system and negate the benefit of having a balanced snake/splitter. Balanced cables reject noise. Ground-lift cables should be used sparingly. *VERY* IMPORTANT: Some older amplifiers (and instrument amplifiers) have electrical ground-lifts on them. These electrical ground-lifts are NOT the same as the XLR ground-lifts (shown in the video). DO NOT disable or shut-off the electrical ground on any amplifier, including stage/instrument amps. Nice choice (Ui24R) for your IEM. Hope this helps.
Wow! What an extensive answer. You answered everything I didn't even think of I need to be answered 😂 thank you so very much. I think you should pin that comment if possible because it answers many question other people can have. Thanks again for clearing up the ground loop hum problem and explaining it in such great detail!
Not necessarily. Unbalanced cables have 1 x conductor wire and 1 x ground wire. Balanced cables (most XLR types) have 2 x conductor wires and 1 x ground wire. It's the 2 x conductor wires that provide most of the noise rejection in mic cables... removing the ground wire on a balanced cable will not add much (if any) noise to a system. We usually use ground-lift cables (like in the video) for monitor runs... but only if a ground-loop is present on an affected output. Many speaker management systems (i.e. dbx driverack) have ground-lift buttons on the rear of the gear near the XLR inputs. For FOH sound, we keep the "Pin 1 Lift" enabled on our drive rack system 100% of the time. No issues.
Good question. A couple of reasons.... 1. For creating ground-lift cables, it only takes a single break in the grounding path (of the cable); once the pin #1 connection is broken (at one end of the cable), there is no need to remove the connection at the other end of the cable. There would be no additional benefit for controlling a ground-loop. 2. (generally stating)... Keeping one end of the cable with pin #1 bonded to the connector will provide some "noise relief" for the cable if static electricity should occur within the cable. With the pin #1 wire still attached on one end only, this will provide a path for any static electricity to be dissipated to (back to the chassis-ground). Not too long ago, I had to convert my Ethercon STP cables to UTP cables because of static electricity issues. Only one end of the Ethercon cables (for the ground/shield) was disconnected... the other end is still bonded; this corrected a lot of issues.
i can just cut the ground wire of a stereo aux cable and the hum will go? like a electrically powered org to pc , cutting the ground wire will eliminate the ground loop? i was using a ground loop isolator but i will try that instead.
Seen your video. What about if my XLR cable ground wire Are solid at pin 1 an 3 an the red an white wire is solid on pin 1 ? I have XLR cables with the RCA plugs
From your description, RCA cable ends (plugs) are not manufactured to be balanced (like they are with XLR connectors), meaning the RCA connectors can only support unbalanced wiring. When using 3-wires on unbalanced connections, pin 1 and pin 3 are usually tied together (inside the connector). This type of setup is when one end of the cable has an XLR balanced connector and the other has something like an RCA or 1/4" unbalanced connector.
A ground-loop "buzz" will be a 60hz sound (bassy sound) and will be rather noticeable (a little loud). Other buzzing in powered speakers (usually at a lower level of volume and at a higher frequency) could be from other equipment causing EMI/RFI noise, or some lights (like florescent lights) that have ballasts in them can add to noise. As well, some cheap (very inexpensive cables) can be noisy by themselves. Also, you could try connecting the power for the GSP speakers to the same circuit as the console. Tracking down "buzzing" sounds in speakers and amplifiers can take awhile; there's a lot of variables involved. What model of GSP speakers are you using?
@@stageleftaudio Gemini GSP-L2200 that'z the model I did try lowering the i don't miss use the volume on them. Maybe it's the XLR cables with the RCA at the end ?
I'm not sure if a ground-lift cable would help your GTX issue. The ground-lift cables shown in the video are for setting up a sound system with multiple power-sources. The hum that is found in sound systems is usually do to a ground loop between XLR cables. Hum issues in instrument amps sometimes have to do with "noise" on the same circuit where the amp is plugged in. Try plugging the GTX in different receptacles around your studio or house... make sure to use receptacles that are far away from where the GTX is currently plugged into. Also, some guitar cables can cause hum issues, try swapping them out.
I've been investigating this as a simple fix as well as creating hum filter cables. Somewhere else suggested putting a 10 nF in line with the ground rather than just snip it. Do you have any experience with these other methods?
+Nathan Schilz This method is a great fix for ground-loops (which are characterized by a 60hz hum); it's quick and free! If you are getting hums/buzzing other than 60 hz., that may be indicative of other issues somewhere in the signal chain. Researching and locating the cause of the hum/buzz will probably yield better results (over the longer term) than placing an nF in line to filter it out. As well, placing a ground-lifted cable on a unit that has an internal hum will not filter out the hum. I have no experience with nF filters, however, I have heard of some people using those to quiet pops and clicks in "stomp-switches" that are used with some instrument and vocal effect units.
The XLR cables (and TRS cables) all have 3 wires and are a balanced cable. Balanced cables are needed to provide noise rejection when running cables longer than about 25 ft (7.6m). Two-conductor cables (Pos. and Gnd.) are unbalanced and do not reject noise. These cables are used mostly for small distances, inter-rack connectivity and anything less than 25 ft. To keep line noise at a minimum, 3 wires are needed (Pos. Neg. & Gnd).
Hi Stageleftaudio. I never have humming noise before I bought a Meyer Sound CP-10 from a local. Currently my QSC power speaker xlr m/f cables plugged in the output of the CP-10 and the xlr m/f cables from the input of the CP-10 to Stereo Masters of the Midas Venice 240 is making humming sound. I tried your way but the humming sounds still there. What is the best way and how I can do to correct this problem? Thank you.
Remove the CP-10 from your audio chain and see if the ground-loop is still there. If it is NOT there, the problem is with the CP-10 EQ. On the back of the EQ there is a ground-life switch. Try selecting the "Lift" side of the switch. Also, if you are using XLR cables, make the switch on the back of the CP-10 is set to "Balanced". There's a lot of variables in troubleshooting ground lift issues. Hopefully, this will get you started.
stageleftaudio Thank you for your replied. Yes when I unplugged the CP-10 from the chain it’s perfect no ground loop hum noise. I did tried the switch on the back the CP-10 and it is no different. (humming sound still there). I used to have the KT DN410 and had no ground loop problem.
The ground-lift modification (in the video) covers issues with signal cables. Tracking down ground-hum related issues can take awhile. If the hum is worse (after doing the modification), it's possible something else on the same circuit has a signal grounding issue; something like noisy/bad power-supplies, fluorescent lights on the same circuit, or possibly something with a motor in it (motors generate EMF which can cause hum). Also, there could be an unbalanced cable somewhere in the "loop" of the signal path, which could include a bad XLR cable. There's a lot of variables involved... What can happen (but not too often), is there could be a ground loop between amplifiers and/or active speakers (at the stage), which would not include any cabling from the console to the stage. Some troubleshooting: Connect everything up as you normally would using non-modified XLR cables. Then, remove one XLR cable (i.e. starting with the main out console cable) and see if the hum disappears. If the hum disappears, there's a signal grounding issue between FOH and where the XLR terminates at the stage. If the hum does NOT go away, the grounding issue is at the stage. Try disconnecting signal cabling (one at a time) from any powered speakers or amplifiers at the stage. The idea is to move through all the connecting XLR cables, unplugging -- test for noise -- then plug back in... move to the next cable. Depending on your setup, you could try temporarily moving everything that needs to be powered, over to one circuit. When everything is connected to one circuit, there (technically) should be no loops to support a ground loop.
Thanks for the video man! My system uses a pair of active subwoofers and a pair of active cabs. If each of the 4 speakers are being run off a different power supply, would I need to use ground lift cables to link the subs to the cabs aswell as sending the signal from the mixer?
It's not very common, but yes, you may need to use a ground lift cable between the powered speakers if their power comes from separate circuits. Test your configuration first... you may not need a ground lift. If using a ground-lift cable at the speakers, you may be ok with not using one for FOH. The biggest problem with ground loops originating from FOH is due to the use of a separate source of power at FOH. What some people do, is pull power (from the stage area where the amps are) to FOH. This greatly reduces the opportunity for a ground loop.
Based upon the source of the ground loop (many times, issues with equipment not related to the sound system), lifting the ground is a valid solution. Tracing the issue of the ground should be the first step before determining if a ground lift should be utilized.
Hello, I was on the verge of buying a ground loop isolator when I saw this...I have a ground loop problem where my graphics card causes interference with my active monitors through ground.When I lift the ground of the power plugs the problem solves but I heard that is dangerous to do.Is this gonna solve my ground loop? Should I cut the ground of the input or the output (my cable is jack to xlr) Thanks
I am not an electrician, but will tell you that you should not lift the ground associated with the power. The ground is used to trip the circuit breaker (or blow a fuse) if a short occurs in the equipment. Without the ground, there is a 100% chance of getting shocked and potentially starting a fire. The symptoms you describe don't exactly sound like a ground loop, but more like electrical noise (i.e. something on the circuit is electrically "noisy" - transformer, ballasts, compressor, etc...) However, if you have equipment plugged into different outlets (circuits) in the room, this could present a ground loop situation. I recommend using an extension XLR cable and lifting the ground on it, instead of modifying your "good" cable. This way, you will be able to test the connectivity to see if the ground lift worked... without needing to modify your good cable.
Isn't this dangerous? And if not, why are those ground connections there in the 1st place? Maybe it's only dangerous when lightning strikes or something?
The ground connection (Pin #1) is what creates a balanced signal in XLR (and TRS) cables; it keeps the noise down. Without the ground, the cable is unbalanced (which can greatly increase noise over long distances). A side effect of having a ground is the potential for a ground loop. A lot of equipment has a ground-lift switch built into them (i.e. dbx driverack 260) and some amplifiers - that can be turned on/off if needed. Lifting the ground affects the audio; it's not used for grounding equipment related to electricity.
+liarschair10 A lot of things that can cause that; though, microphone cables rarely ever need to have their ground lifted. Most fixes to ground lifts occur by "breaking" the signal path where two separate power sources exist (i.e. the signal run between FOH and monitors or FOH and amplifier rack), not from an audio source like a mic. Many times, microphone shocking can be due to bad mic cables with energized wires touching the frame of a mic or of the mixing board. Mic cables should be tested regularly to ensure no issues.
They can be used at FOH or at the stage. Mostly used in the signal chain between the stage (snake) and the FOH console. They are also sometimes used in an amplifier rack when different sources of electricity are used to power multiple amplifiers... specifically, if you are daisy chaining amplifiers of which are all powered from different electrical outlets.
If youre doing this, its because something else is wrong. If something else is wrong with your equipment this can be deadly. If youre a sound engineer doing this, dont tell anybody if you value your job.
Remember... we are lifting the ground for audio, NOT electrical. To avoid creating ground-lift cables, some manufactures have incorporated ground-lift switches in their gear (i.e. dbx drive-rack units), which do the same thing as the ground-lift cables.
This means the hum you are hearing is probably not from a ground loop. Other sources of humming (on the signal cables) can include rectifiers, transformers, heavy loaded items (compressors), and even some light ballasts.. Also, a hum could be coming from the amplifier (due to a fault/short in the amplifier). If you have 2 amplifiers producing the same frequency range (both amplifiers are daisy chained), a ground loop can occur between the amplifiers (from the daisy chaining cable)... if the amplifiers are getting their power from difference sources. If this were to occur, you would need a ground loop cable (as a daisy chaining cable) between the amplifiers.
Lifting the ground of an XLR is common. The ground removal in an XLR is for managing signal/line levels only. It does not affect the electricity used for the equipment. Many stage boxes have ground-lift switches on them (for each channel), as well, some equipment (drive-racks, cross-overs, DI's, etc...) have ground lift switches built-in to them (to be switched on/off as needed).
After a lot of research, I settled on this approach and it definitely works. I read about the principles elsewhere, but came to the video to see a visual demonstration. I've suffered ground loop problems for 10 years(!) with unbalanced sources connected to balanced inputs on my active monitors, which need to be plugged in to different wall sockets due to the layout of the room. There are other recommended fixes out there, including lifting the ground pin on the power cable (dangerous) and spending money on isolators (can degrade sound, unless you spend a ton) hum removers, DI boxes, etc. This was my preferred option. I wanted a non-destructive method in case it didn't resolve the humming or I got too much unwanted interference, so I de-soldered the cable from pin 1 and folded it back against the sheath. Thanks for the video.
Thank you for the comment. Most of the time, the boxes that are sold to stop the "humming" are targeted for line noise and other "internal" noise producers, not for ground-loop situations. Having several ground-loop cables on hand will eliminate nearly all ground-loop situations. The idea is to know if what you are hearing is from a ground loop, or from something internal.
Chucking in the obligatory reply - NEVER TAKE THE EARTH OUT OF A POWER SUPPLY, EVER.
Someone at my university died doing that the year before I got there. Scary stuff.
(Sounds like you knew all this already 😅 just for anyone else reading...)
This just saved the sound on a livestream right now from groundloop hum, thanks!
Glad it helped!
thank you so much!!! I've been trying to solve this problem with my studio monitors for YEARS!!!
Thank you for the explanation... solved my problem 👍
Thanks for this, it sorted my problem out!
Great to hear!
I'm surprised there aren't many videos talking about this issue... In my basement home studio, I have a mixer plugged into an outlet, and a Mackie powered speaker in another outlet at the other end of the room... i'm getting a bad ground loop, looking forward testing this out. Thanks!
I’m having this issue with my preamp which has a separate power supply with a buzzing transformer that you can hear. The transformer hum is making its way into the audio path via the line input when sending audio from the computer into the line and back. The mic or DI are fine.
Any idea if this ground lift cable would be worth a try?
Looks like you are using home audio equipment...? I'm not sure about home audio gear. Though, if all your gear (including the preamp) are connected to the same circuit, and there is still a humming sound, this could be an issue with a transformer or something else (another noisy transformer) on the same circuit (refrigerator, florescent lights, etc...). However, sometimes humming/buzzing can be the result of an impedance mismatch between components. An actual humming sound is most always a ground-loop; whereas a buzzing sound is most always an issue with a piece of equipment. From what you described, a ground-lift cable may not correct the issue. When we connect computers/MP3/iPads/etc... into our system, we use a passive transformer that converts the impedance (of the device connected) to match what the sound system is expecting to see.
Instead of using Diags to cut the connection, you could desolder the ground and tape it off, which would be reversible.
10 minutes, that's impressive.
tried this just now. no safety or damage issues. it works fine. however, if you are using any xlr adapters (i.e. the triton fethead) which use all 3 pins, they will no longer be compatible with this modified cable. ecommended to try out on a spare xlr cable, but dont do it on the only one you have.
Hello there, great video! Just a quick question. I'm creating my own passive splitter snake (something like the seismic audio one). Should I be worried about this and cut the pins 1 on all of the connectors just in case? Two of my microphones are condenser, wouldn't that affect phantom power? And also our guitarist uses active DI where phantom power needs to be provided as well. I'm curious if I should cut the pins 1 just in case or you advise to have couple of lifted cables made aside. Thanks a lot, liked and subscribed!
Thanks for your comment. Good question. I would NOT cut the pins on any of the connectors on the splitter. Instead, (just as you said), pick up several short XLR cables and cut the pins in those... then use those cables on problem inputs only. I have about a dozen 1 ft. long cables that are ground-lifted. Also, if you are using a speaker management system (like the dbx 260), some of those units have built-in ground-lift switches on the rear of the units (usually next to the inputs). For most of the shows we do, I use the built-in ground-lift on our dr-260. I occasionally will need to use a ground-lift cable on the monitor signals (at the monitor console).
For the DI's, many of those should have a ground-lift switch on them already (ground-lift switches are somewhat now normal on many DIs). If the DI does not have a ground-lift, just use a short ground-lifted cable on it. Phantom power should still pass with a ground-lift activated.
@@stageleftaudio Thank you so much for your reply! I'm basically building the split snake for the band where we use Soundcraft Ui24R as our IEM mixer and I'm not aware if there are any options to ground lift individual channel. With your experience what would you say is the most susceptible input type for ground humm? Dynamic mics, condenser mics, DI boxes, DI outputs from bass amp or the PA speakers? It's 3 of us in a band, acoustic guitar, bass, drums and all 3 of us sing, so I'm just curious how many of those ground-lifted cables should I make. If we use complete mic setup it's cca 14 inputs so should I have 14 short ground-lifted cables on hand? Can it happen on all of the inputs at once? Any info will be appreciated, thanks a lot!
Thanks for your setup information. This may be more information than what you need for your type of setup, but hopefully it will give you a broader picture of how ground-loops (hum) occur in a sound system. Hopefully it may help you decide how to handle a potential hum. The ground-loop in a system is not caused by the type of microphone or DI boxes used (unless there is something internally wrong with them). Though, the outputs on guitar and bass amps (including the built-in DIs on these amps) are sometimes prone to signal grounding issues, which can cause hum. Most all of the hum (ground loop) you hear in a sound system is caused by a continuous balanced (XLR) signal path between two different power sources. Pin #1 in an XLR cable (the ground) provides the only signal path that can traverse an entire system. When Pin #1 is connected (through all the grounds in a system), it creates a large physical loop (which generates interference) between at least two different power sources. For example, a power source could be at the FOH mixing location (for the console), and another power source could be at the stage (for the main PA, instruments, monitors, etc...). The FOH and stage locations would be connected (through a signal) using a multi-core snake; of which the snake would have many pin #1 connections. Removing the connection on pin #1 (as shown in the video) for the main output of the console breaks the ground-loop circuit between the two locations, therefore eliminating the hum. This also applies to monitor sends (if mixing monitors from FOH). Sometimes, it doesn't matter where the break occurs in the loop, just as long as there is a break. But also, not every setup has a ground-loop problem!
The other issue that can cause hum (not related to ground-loops) is from some older instrument (mostly guitar) amplifiers that have wiring or other modification issues inside the instrument amp. The hum produced by these older amps gets amplified. Using a ground-lift cable on these types of amps will not correct the hum. Any hum from these older amps usually indicates it needs something fixed internally.
It is possible to have multiple ground-loops in a sound system. Some of the ground loops can be localized to the stage from using multiple stage circuits when using multiple FOH amplifiers (i.e. sending the same FOH signal to many amplifiers). A ground loop (hum) can occur between amplifiers. Using a ground-lift XLR cable (as in the video) between amplifiers can eliminate the hum.
You should only need a few ground-lift cables at most. In my large sound system, I may occasionally only need two ground-lift cables, and that would be used in the sending of monitor signals from the FOH console to a monitor amps. As well, all of my DI boxes have ground-lifts on them that I can activate or de-activate as needed for any instrument amp.
IMPORTANT: Tracking down ground-loops (hum) in a sound system can take some time and may require good trouble-shooting skills. Ground-loops localized to the stage are harder to track down than those for FOH. Some instrument amps have XLR ground-lifts incorporated in them (usually at the output)... use those first before inserting any ground-lift cable. You should not use ground-lift cables on every input, because it can introduce a lot of noise into the system and negate the benefit of having a balanced snake/splitter. Balanced cables reject noise. Ground-lift cables should be used sparingly.
*VERY* IMPORTANT: Some older amplifiers (and instrument amplifiers) have electrical ground-lifts on them. These electrical ground-lifts are NOT the same as the XLR ground-lifts (shown in the video). DO NOT disable or shut-off the electrical ground on any amplifier, including stage/instrument amps.
Nice choice (Ui24R) for your IEM.
Hope this helps.
Wow! What an extensive answer. You answered everything I didn't even think of I need to be answered 😂 thank you so very much. I think you should pin that comment if possible because it answers many question other people can have. Thanks again for clearing up the ground loop hum problem and explaining it in such great detail!
does this cause the cable to be unbalanced?
Not necessarily. Unbalanced cables have 1 x conductor wire and 1 x ground wire. Balanced cables (most XLR types) have 2 x conductor wires and 1 x ground wire. It's the 2 x conductor wires that provide most of the noise rejection in mic cables... removing the ground wire on a balanced cable will not add much (if any) noise to a system. We usually use ground-lift cables (like in the video) for monitor runs... but only if a ground-loop is present on an affected output. Many speaker management systems (i.e. dbx driverack) have ground-lift buttons on the rear of the gear near the XLR inputs. For FOH sound, we keep the "Pin 1 Lift" enabled on our drive rack system 100% of the time. No issues.
Just curious why you would leave one side’s ground connected vs cutting both sides. Thanks!
Good question. A couple of reasons....
1. For creating ground-lift cables, it only takes a single break in the grounding path (of the cable); once the pin #1 connection is broken (at one end of the cable), there is no need to remove the connection at the other end of the cable. There would be no additional benefit for controlling a ground-loop.
2. (generally stating)... Keeping one end of the cable with pin #1 bonded to the connector will provide some "noise relief" for the cable if static electricity should occur within the cable. With the pin #1 wire still attached on one end only, this will provide a path for any static electricity to be dissipated to (back to the chassis-ground). Not too long ago, I had to convert my Ethercon STP cables to UTP cables because of static electricity issues. Only one end of the Ethercon cables (for the ground/shield) was disconnected... the other end is still bonded; this corrected a lot of issues.
@@stageleftaudio Thank you!!!
i can just cut the ground wire of a stereo aux cable and the hum will go? like a electrically powered org to pc , cutting the ground wire will eliminate the ground loop? i was using a ground loop isolator but i will try that instead.
Do I have to do it to both cables or just one side
Just one side.
@stageleftaudio thanks
Seen your video. What about if my XLR cable ground wire Are solid at pin 1 an 3 an the red an white wire is solid on pin 1 ? I have XLR cables with the RCA plugs
From your description, RCA cable ends (plugs) are not manufactured to be balanced (like they are with XLR connectors), meaning the RCA connectors can only support unbalanced wiring. When using 3-wires on unbalanced connections, pin 1 and pin 3 are usually tied together (inside the connector). This type of setup is when one end of the cable has an XLR balanced connector and the other has something like an RCA or 1/4" unbalanced connector.
@@stageleftaudio
So what do you suggest ? I have a set of Gemini's GSP power speakers that have the buzzing sound coming from them
A ground-loop "buzz" will be a 60hz sound (bassy sound) and will be rather noticeable (a little loud). Other buzzing in powered speakers (usually at a lower level of volume and at a higher frequency) could be from other equipment causing EMI/RFI noise, or some lights (like florescent lights) that have ballasts in them can add to noise. As well, some cheap (very inexpensive cables) can be noisy by themselves. Also, you could try connecting the power for the GSP speakers to the same circuit as the console. Tracking down "buzzing" sounds in speakers and amplifiers can take awhile; there's a lot of variables involved.
What model of GSP speakers are you using?
@@stageleftaudio
Gemini GSP-L2200 that'z the model I did try lowering the i don't miss use the volume on them. Maybe it's the XLR cables with the RCA at the end ?
@@stageleftaudio
What about if i resolder Pin 2 and 3 are for audio, Pin 1 is for ground on my XLR cables with RCA at the end ?
My Fender Mustang amplifier had ground lift button, their new GTX amp does not.
The new GTX has a hum - will this fix this situation?
I'm not sure if a ground-lift cable would help your GTX issue. The ground-lift cables shown in the video are for setting up a sound system with multiple power-sources. The hum that is found in sound systems is usually do to a ground loop between XLR cables. Hum issues in instrument amps sometimes have to do with "noise" on the same circuit where the amp is plugged in. Try plugging the GTX in different receptacles around your studio or house... make sure to use receptacles that are far away from where the GTX is currently plugged into. Also, some guitar cables can cause hum issues, try swapping them out.
I've been investigating this as a simple fix as well as creating hum filter cables. Somewhere else suggested putting a 10 nF in line with the ground rather than just snip it. Do you have any experience with these other methods?
+Nathan Schilz This method is a great fix for ground-loops (which are characterized by a 60hz hum); it's quick and free! If you are getting hums/buzzing other than 60 hz., that may be indicative of other issues somewhere in the signal chain. Researching and locating the cause of the hum/buzz will probably yield better results (over the longer term) than placing an nF in line to filter it out. As well, placing a ground-lifted cable on a unit that has an internal hum will not filter out the hum.
I have no experience with nF filters, however, I have heard of some people using those to quiet pops and clicks in "stomp-switches" that are used with some instrument and vocal effect units.
Hello, Why do we not make all XLR cables this way? Why would we ever want pin one connected on both ends?
The XLR cables (and TRS cables) all have 3 wires and are a balanced cable. Balanced cables are needed to provide noise rejection when running cables longer than about 25 ft (7.6m). Two-conductor cables (Pos. and Gnd.) are unbalanced and do not reject noise. These cables are used mostly for small distances, inter-rack connectivity and anything less than 25 ft. To keep line noise at a minimum, 3 wires are needed (Pos. Neg. & Gnd).
I thought the first pin is the on the right, not left (with male XLR)
1 pin signal
3 pin signal
2 ground
10mins to say "cut that wire".
I think this is not a groung lift but it is sheeld lift. Anyone else think so, or am i wrong?
Good point. The ground is the shield, just as the shield is the ground.
Hi Stageleftaudio.
I never have humming noise before I bought a Meyer Sound CP-10 from a local. Currently my QSC power speaker xlr m/f cables plugged in the output of the CP-10 and the xlr m/f cables from the input of the CP-10 to Stereo Masters of the Midas Venice 240 is making humming sound. I tried your way but the humming sounds still there. What is the best way and how I can do to correct this problem?
Thank you.
Remove the CP-10 from your audio chain and see if the ground-loop is still there. If it is NOT there, the problem is with the CP-10 EQ. On the back of the EQ there is a ground-life switch. Try selecting the "Lift" side of the switch. Also, if you are using XLR cables, make the switch on the back of the CP-10 is set to "Balanced".
There's a lot of variables in troubleshooting ground lift issues. Hopefully, this will get you started.
stageleftaudio
Thank you for your replied. Yes when I unplugged the CP-10 from the chain it’s perfect no ground loop hum noise. I did tried the switch on the back the CP-10 and it is no different. (humming sound still there). I used to have the KT DN410 and had no ground loop problem.
Sounds like there could be an internal issue with the CP-10.
Any suggestions on where I could buy those cables to make my own jacks ?
Any music store should have these cables, or Amazon.
I just performed this mod on my XLR's and it actually made the humming noise much louder and more prevalent. Any other suggestions to fix the issue?
The ground-lift modification (in the video) covers issues with signal cables. Tracking down ground-hum related issues can take awhile. If the hum is worse (after doing the modification), it's possible something else on the same circuit has a signal grounding issue; something like noisy/bad power-supplies, fluorescent lights on the same circuit, or possibly something with a motor in it (motors generate EMF which can cause hum). Also, there could be an unbalanced cable somewhere in the "loop" of the signal path, which could include a bad XLR cable.
There's a lot of variables involved... What can happen (but not too often), is there could be a ground loop between amplifiers and/or active speakers (at the stage), which would not include any cabling from the console to the stage.
Some troubleshooting: Connect everything up as you normally would using non-modified XLR cables. Then, remove one XLR cable (i.e. starting with the main out console cable) and see if the hum disappears. If the hum disappears, there's a signal grounding issue between FOH and where the XLR terminates at the stage. If the hum does NOT go away, the grounding issue is at the stage. Try disconnecting signal cabling (one at a time) from any powered speakers or amplifiers at the stage.
The idea is to move through all the connecting XLR cables, unplugging -- test for noise -- then plug back in... move to the next cable.
Depending on your setup, you could try temporarily moving everything that needs to be powered, over to one circuit. When everything is connected to one circuit, there (technically) should be no loops to support a ground loop.
Thanks for the video man! My system uses a pair of active subwoofers and a pair of active cabs. If each of the 4 speakers are being run off a different power supply, would I need to use ground lift cables to link the subs to the cabs aswell as sending the signal from the mixer?
It's not very common, but yes, you may need to use a ground lift cable between the powered speakers if their power comes from separate circuits. Test your configuration first... you may not need a ground lift. If using a ground-lift cable at the speakers, you may be ok with not using one for FOH. The biggest problem with ground loops originating from FOH is due to the use of a separate source of power at FOH. What some people do, is pull power (from the stage area where the amps are) to FOH. This greatly reduces the opportunity for a ground loop.
If you have a ground loop in your system lifting the ground on a balanced audio cable is the wrong way to try to fix it
Based upon the source of the ground loop (many times, issues with equipment not related to the sound system), lifting the ground is a valid solution. Tracing the issue of the ground should be the first step before determining if a ground lift should be utilized.
Hello, I was on the verge of buying a ground loop isolator when I saw this...I have a ground loop problem where my graphics card causes interference with my active monitors through ground.When I lift the ground of the power plugs the problem solves but I heard that is dangerous to do.Is this gonna solve my ground loop? Should I cut the ground of the input or the output (my cable is jack to xlr) Thanks
I am not an electrician, but will tell you that you should not lift the ground associated with the power. The ground is used to trip the circuit breaker (or blow a fuse) if a short occurs in the equipment. Without the ground, there is a 100% chance of getting shocked and potentially starting a fire.
The symptoms you describe don't exactly sound like a ground loop, but more like electrical noise (i.e. something on the circuit is electrically "noisy" - transformer, ballasts, compressor, etc...) However, if you have equipment plugged into different outlets (circuits) in the room, this could present a ground loop situation. I recommend using an extension XLR cable and lifting the ground on it, instead of modifying your "good" cable. This way, you will be able to test the connectivity to see if the ground lift worked... without needing to modify your good cable.
Isn't this dangerous? And if not, why are those ground connections there in the 1st place? Maybe it's only dangerous when lightning strikes or something?
The ground connection (Pin #1) is what creates a balanced signal in XLR (and TRS) cables; it keeps the noise down. Without the ground, the cable is unbalanced (which can greatly increase noise over long distances). A side effect of having a ground is the potential for a ground loop. A lot of equipment has a ground-lift switch built into them (i.e. dbx driverack 260) and some amplifiers - that can be turned on/off if needed. Lifting the ground affects the audio; it's not used for grounding equipment related to electricity.
isn't this where the singer's gets the HELL knocked out of them when their lips touch the metal grill on the wind screen?
+liarschair10 A lot of things that can cause that; though, microphone cables rarely ever need to have their ground lifted. Most fixes to ground lifts occur by "breaking" the signal path where two separate power sources exist (i.e. the signal run between FOH and monitors or FOH and amplifier rack), not from an audio source like a mic.
Many times, microphone shocking can be due to bad mic cables with energized wires touching the frame of a mic or of the mixing board. Mic cables should be tested regularly to ensure no issues.
Where are use this tayp cables.
They can be used at FOH or at the stage. Mostly used in the signal chain between the stage (snake) and the FOH console. They are also sometimes used in an amplifier rack when different sources of electricity are used to power multiple amplifiers... specifically, if you are daisy chaining amplifiers of which are all powered from different electrical outlets.
Can get a good shock if used on a microphone be careful! everything is fine
If youre doing this, its because something else is wrong.
If something else is wrong with your equipment this can be deadly.
If youre a sound engineer doing this, dont tell anybody if you value your job.
Remember... we are lifting the ground for audio, NOT electrical. To avoid creating ground-lift cables, some manufactures have incorporated ground-lift switches in their gear (i.e. dbx drive-rack units), which do the same thing as the ground-lift cables.
@@stageleftaudio I think you know what youre doing, but neighter the people watching this or the backline crew.
Nope didn't work for me Bro I still get the humming in my speakers
This means the hum you are hearing is probably not from a ground loop. Other sources of humming (on the signal cables) can include rectifiers, transformers, heavy loaded items (compressors), and even some light ballasts.. Also, a hum could be coming from the amplifier (due to a fault/short in the amplifier). If you have 2 amplifiers producing the same frequency range (both amplifiers are daisy chained), a ground loop can occur between the amplifiers (from the daisy chaining cable)... if the amplifiers are getting their power from difference sources. If this were to occur, you would need a ground loop cable (as a daisy chaining cable) between the amplifiers.
omg thanks man ...it works for me! :)
but i dont know if that is safety?
Lifting the ground of an XLR is common. The ground removal in an XLR is for managing signal/line levels only. It does not affect the electricity used for the equipment. Many stage boxes have ground-lift switches on them (for each channel), as well, some equipment (drive-racks, cross-overs, DI's, etc...) have ground lift switches built-in to them (to be switched on/off as needed).
stageleftaudio thanks so much u save me Money😊