TopHouse
Nine times out of ten, if you have a buzzing or humming problem on your speaker outputs, it's caused by what is known as a ground loop. This is where two pieces of equipment are operating, usually using different outlets, or in the case of a laptop, has no true earth (psu) The buzz or hum is caused by the mains potential trying to equalise using the only path it has, the earth line. Obviously it cannot equalise so it creates a loop. Hence "ground loop interference"
This is very common in laptops, you can easily tell if you have a ground loop. Using PSU, buzz and/or hum. Disconnect PSU (battery power) No buzz or hum.
There are many suggested ways of curing this problem, the most simple and safest for a DJ is simply to use what are known as "Ground Loop Isolators" These look like a little plastic case with inputs and outputs and are simply plugged in between equipment outputs and mixer inputs. All that is inside is a basic transformer that 'isolates' the loop.
There is no point in me adding a link to a supplier since there are VDJ users reading this from all over the world, just do a google for "ground Loop Isolator" and you will find what you want. You will need to buy one of these for each stereo channel going into the mixer.
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
Simple maths
Ground loop isolators = cheap
Your life = whatever value you or your loved ones put on it. ie priceless!
NOTE, computers are very elictrically noisy things anyway, you have cooling fans, GFX board fans, processors cycling, etc etc, ground loop isolators can eliminate a lot of that noise.
This is very common in laptops, you can easily tell if you have a ground loop. Using PSU, buzz and/or hum. Disconnect PSU (battery power) No buzz or hum.
There are many suggested ways of curing this problem, the most simple and safest for a DJ is simply to use what are known as "Ground Loop Isolators" These look like a little plastic case with inputs and outputs and are simply plugged in between equipment outputs and mixer inputs. All that is inside is a basic transformer that 'isolates' the loop.
There is no point in me adding a link to a supplier since there are VDJ users reading this from all over the world, just do a google for "ground Loop Isolator" and you will find what you want. You will need to buy one of these for each stereo channel going into the mixer.
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
Simple maths
Ground loop isolators = cheap
Your life = whatever value you or your loved ones put on it. ie priceless!
NOTE, computers are very elictrically noisy things anyway, you have cooling fans, GFX board fans, processors cycling, etc etc, ground loop isolators can eliminate a lot of that noise.
Posted Mon 01 Oct 07 @ 3:42 pm
DJ-ALF
I wanted to add something like this in FAQ section:
http://www.virtualdj.com/forums/74088/General_Discussion/_READ_ME_BEFORE_POSTING__FAQ_-_Frequently_asked_questions.html
will suggest Sky to add it there, if that's ok with you?
Good post BTW! ;)
http://www.virtualdj.com/forums/74088/General_Discussion/_READ_ME_BEFORE_POSTING__FAQ_-_Frequently_asked_questions.html
will suggest Sky to add it there, if that's ok with you?
Good post BTW! ;)
Posted Mon 01 Oct 07 @ 4:34 pm
Timmyg1978
Nice work tophouse, kudos;^]
Posted Mon 01 Oct 07 @ 4:39 pm
TopHouse
hehehe, is that another star I feel coming on...... ;o)
Posted Mon 01 Oct 07 @ 4:58 pm
Superstom
TopHouse wrote :
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
Tophouse, you're not completely right. The above statement is right for a refridgerator or a washing machine. MOst of the humming problems are caused by power adapters for laptops. In those power supplies only the power supply itself is connected with the earth cable. Fro the power supply to the laptop are only 2 wires (no earth wire). So the only way that the adapter is helping is when the power adapter has a problem (wire or circuit board connected to the box). While most power supplies are also made from plastic, you can't even get an electrical shock.
On the other hand lots of wall sockets in homes dont have an earth connected.
So running without earth connected isn't that bad, or dangerous.
Ewout
Posted Mon 01 Oct 07 @ 9:01 pm
Rune (DJ-In-Norway)
SELECTED GUIDES
Added to selected guides :)
Posted Mon 01 Oct 07 @ 9:04 pm
TopHouse
Takk Herr Norge
Posted Mon 01 Oct 07 @ 9:13 pm
TopHouse
Superstom wrote :
Tophouse, you're not completely right. The above statement is right for a refridgerator or a washing machine.
TopHouse wrote :
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
WARNING WILL ROBINSON
Some people will advise you to remove the earth pins from plugs or use 3 pin to 2 pin converter plugs. THIS IS DANGEROUS! The earth line to a piece of equipment is put there as a safety precaution to prevent electric shock in the case of a fault. Putting this simply... DO NOT DO THIS! YOU COULD GET ELECTROCUTED! EVEN WORSE YOU COULD DIE!!
Tophouse, you're not completely right. The above statement is right for a refridgerator or a washing machine.
Or a shuttle, or a desktop, or a rackmounted PC, or a mixer, or an amplifier! Removing earth pins is wrong and dangerous period!
Quote :
On the other hand lots of wall sockets in homes dont have an earth connected.
in outer mongolia maybe, but in many countries, including the UK, not having earth in mains sockets is ILLEGAL!
Posted Mon 01 Oct 07 @ 9:16 pm
Rune (DJ-In-Norway)
TopHouse wrote :
Takk Herr Norge
loool
Posted Mon 01 Oct 07 @ 9:16 pm
TopHouse
there's that 'lol' echoing in the fjords again! ;o)
Posted Mon 01 Oct 07 @ 9:19 pm
Superstom
Tophouse,
I agree with you on desktop or shuttle machines, however for most laptops it is not that important. Most older homes in the Netherlands have only sockets with earth connection in the kitchen and for the washing machine. Houses that are currently build should have earth leads on all sockets.
For work I stayed a couple of times in the UK and in my hotel room I could not plugin my laptop, while the socket had only 2 connections. In europe most connections are well done, but I have been in some countries where power connections are much more dangerous than connection your laptop without earth.
Ewout
I agree with you on desktop or shuttle machines, however for most laptops it is not that important. Most older homes in the Netherlands have only sockets with earth connection in the kitchen and for the washing machine. Houses that are currently build should have earth leads on all sockets.
For work I stayed a couple of times in the UK and in my hotel room I could not plugin my laptop, while the socket had only 2 connections. In europe most connections are well done, but I have been in some countries where power connections are much more dangerous than connection your laptop without earth.
Ewout
Posted Mon 01 Oct 07 @ 10:58 pm
TopHouse
Superstom wrote :
Tophouse,
I agree with you on desktop or shuttle machines, however for most laptops it is not that important. Most older homes in the Netherlands have only sockets with earth connection in the kitchen and for the washing machine. Houses that are currently build should have earth leads on all sockets.
For work I stayed a couple of times in the UK and in my hotel room I could not plugin my laptop, while the socket had only 2 connections. In europe most connections are well done, but I have been in some countries where power connections are much more dangerous than connection your laptop without earth.
Ewout
I agree with you on desktop or shuttle machines, however for most laptops it is not that important. Most older homes in the Netherlands have only sockets with earth connection in the kitchen and for the washing machine. Houses that are currently build should have earth leads on all sockets.
For work I stayed a couple of times in the UK and in my hotel room I could not plugin my laptop, while the socket had only 2 connections. In europe most connections are well done, but I have been in some countries where power connections are much more dangerous than connection your laptop without earth.
Ewout
That maybe the case in semi 3rd world countries, however much dangersous, why argue with the FACT that interfering with earths can result in DEADLY electrocution and is NOT the recommended fix and that ground loop isolators are!
Might I add at this point that in my previous life I was an electronics engineer in the UK Royal Air Force working on Tornado GR1's and after that was a qualified domestic electrician.
Of course, if anyone want to disregard my advice, feel free, please don't let your relatives give me any crap when you are a black & crispy item on the end of a dj console somewhere!
Posted Mon 01 Oct 07 @ 11:46 pm
Timmyg1978
My dad earned his masters electrician at Massanutten Technical Center, and later went back to teach there. His advice is the same, though he does add the double prong adapters are generaly safe, but actualy removing the grounding post is extremely dangerous on any piece of electronics that require it. I guess there's always an exception to the rule, and maybe qualified technicians can do it safely, but the safest way to tackle the problem is the isolators, hands down. So if you need to lose the ground/ earth pin due to double socket outlets, use an adapter & only on the main powerstrip connected to that outlet. If the problem is audio, just use the isolators;^]
Posted Tue 02 Oct 07 @ 1:21 am
cstoll
Look the bottom line is that there is differencing in opinions and since there is not a World Wide Electrical Standard all the points are valid. And, if in certain cases, with certain electric systems that a WARNING should be given if a stupid act is about to occur - then I would side on the side of CAUTION and have the Warning be made.
I mean come on, here in the USA; lawyers love this kind of dialog!! That's how we ended up with stickers on vending machines warning users not to tip the machines as they could kill you. WARNING on the side of CAUTION is not a bad thing, sometimes its the idiot that needed it.
So, now the topic is total back on topic of BUZZING and HUMMING - Ground Loop and use an ISOLATOR or a GROUND LIFT solution.
cstoll
I mean come on, here in the USA; lawyers love this kind of dialog!! That's how we ended up with stickers on vending machines warning users not to tip the machines as they could kill you. WARNING on the side of CAUTION is not a bad thing, sometimes its the idiot that needed it.
So, now the topic is total back on topic of BUZZING and HUMMING - Ground Loop and use an ISOLATOR or a GROUND LIFT solution.
cstoll
Posted Tue 02 Oct 07 @ 2:48 am
TopHouse
Cstoll, a ground lift is not the same as an earth lift, this may cause some confusion here as the words 'ground' and 'earth' do get transposed regularly in electrical discussion.
Please be aware that if you have a piece of equipment with a "ground lift" button. This IS NOT removing electrical earth, please DO NOT assume this.
Ground lift on audio equipment means lifting the AUDIO ground, that is, the outer core of your audio leads connecting equipment together, for instance the outer on your phono to phono leads.
Let me explain, and in this explanation the word EARTH means electrical earth, as the earth in a plug. The word GROUND means 'audio ground' that is, the outside wire on your phono and jack plugs etc which are usually in the form of a braid, wrapped around the inner core.
OK, imagine you have an amplifier and a mixer, both are plugged into the mains, now the GROUND is usually CONNECTED to the EARTH inside the equipment, most times this is fine and causes no problems, the reason they do this is that earthing the ground cable makes the ground act like a shield (and why outer cores are often called 'shield' as any interference absorbed by the cable will just leak to EARTH.
In a ground loop circumstance, there are two different electrical potentials in the two pieces of equipment. To simplify this, the connected equipment will work like a set of scales, it wants to balance, simplifying again, lets say there's 10 volts on an amp chassis and nine on the mixer (this is for illustration purposes only) The two voltages want to balance or equalise, the only route it has, is the one that connects the two pieces of equipment, that is, the GROUND of your audio leads, so it travels down those, the thing is, it never equalises as they are connected to the mains, so the difference in electrical potential doesn't change. THIS is a ground loop.
So, to stop that power leaking down the GROUND, you use the GROUND LIFT, which isolates GROUND from EARTH (sometimes completely, sometimes it just puts a resistor in line) This doesn't always work, hence needing ground loop isolators.
So endeth the lesson!
Trust me on this, it's all right and can be verified by searching on the net.
so again REMOVING "EARTH" FROM AN ITEM CAN RESULT IN DEATH!!!!!!!!!!!!!!!!
Something you should be aware of, VOLTAGE does not kill! It is the current that kills, there are huge transformers in some amplifiers that contain a huge amount of current. Bear in mind that UK mains is rated at 13 amp on the socket side (32 amp beyond that) now bear in mind that above 100 mA (0.1 of an amp) can be LETHAL
More info:-
http://en.wikipedia.org/wiki/Electric_shock
http://www.record-producer.com/learn.cfm?a=4067
Please be aware that if you have a piece of equipment with a "ground lift" button. This IS NOT removing electrical earth, please DO NOT assume this.
Ground lift on audio equipment means lifting the AUDIO ground, that is, the outer core of your audio leads connecting equipment together, for instance the outer on your phono to phono leads.
Let me explain, and in this explanation the word EARTH means electrical earth, as the earth in a plug. The word GROUND means 'audio ground' that is, the outside wire on your phono and jack plugs etc which are usually in the form of a braid, wrapped around the inner core.
OK, imagine you have an amplifier and a mixer, both are plugged into the mains, now the GROUND is usually CONNECTED to the EARTH inside the equipment, most times this is fine and causes no problems, the reason they do this is that earthing the ground cable makes the ground act like a shield (and why outer cores are often called 'shield' as any interference absorbed by the cable will just leak to EARTH.
In a ground loop circumstance, there are two different electrical potentials in the two pieces of equipment. To simplify this, the connected equipment will work like a set of scales, it wants to balance, simplifying again, lets say there's 10 volts on an amp chassis and nine on the mixer (this is for illustration purposes only) The two voltages want to balance or equalise, the only route it has, is the one that connects the two pieces of equipment, that is, the GROUND of your audio leads, so it travels down those, the thing is, it never equalises as they are connected to the mains, so the difference in electrical potential doesn't change. THIS is a ground loop.
So, to stop that power leaking down the GROUND, you use the GROUND LIFT, which isolates GROUND from EARTH (sometimes completely, sometimes it just puts a resistor in line) This doesn't always work, hence needing ground loop isolators.
So endeth the lesson!
Trust me on this, it's all right and can be verified by searching on the net.
so again REMOVING "EARTH" FROM AN ITEM CAN RESULT IN DEATH!!!!!!!!!!!!!!!!
Something you should be aware of, VOLTAGE does not kill! It is the current that kills, there are huge transformers in some amplifiers that contain a huge amount of current. Bear in mind that UK mains is rated at 13 amp on the socket side (32 amp beyond that) now bear in mind that above 100 mA (0.1 of an amp) can be LETHAL
More info:-
http://en.wikipedia.org/wiki/Electric_shock
http://www.record-producer.com/learn.cfm?a=4067
Posted Tue 02 Oct 07 @ 11:41 am
sirslick
The easiest way to get rid of the buzz/humm is to purchase a 3-prong to 2-prong electrical adapter. You can buy them for less than $5 at most hardware stores. Simply attach the adapter to your outlet and then plug it into the wall...
Posted Wed 17 Oct 07 @ 4:44 pm
TopHouse
is there a smiley for banging your head against a wall?
Posted Wed 17 Oct 07 @ 5:39 pm
Charlie Five
I always carry a ground loop isolator in my bag. As well as extra RCA's and various adapters. You never know when you will need them.
Posted Wed 17 Oct 07 @ 6:49 pm
thefrankster
Actually, while the three to two prong mod will work if you don't ground the adapter, you now have ungrounded and potentially danderous equipment.
Never defeat a ground. All you need is an audio isolator or a ground loop isolator ala car audio. They are very cheap ($5.00) and eliminate hum and buzzes even better than removing grounds, and are a lot safer. (I was typing at the same time as Charl1e - lol)
Never defeat a ground. All you need is an audio isolator or a ground loop isolator ala car audio. They are very cheap ($5.00) and eliminate hum and buzzes even better than removing grounds, and are a lot safer. (I was typing at the same time as Charl1e - lol)
Posted Wed 17 Oct 07 @ 6:52 pm
Paz75
THere is a little known fact about laptop supplies and ground loops. Most commerical electronic manufacturers dont really care about ground loops because in truth, the proper parts to eliminate this properly are horribly expensive which defeats the purpose of being a 'commerical electronics manufacturer'.
Your laptop uses transformer which uses IC circuits to regulate the onflow current based demand from the laptop. This actually creates a very instable grounding and very definitley creates noise, especially in club environments which have lighting involved. Essentially a club technician will put lights on a separate line than sound. What they dont realize that a laptop DJ's laptop has the same behaviour as the lights so putting it on the sound line is actually a pretty bad thing.
Traditional tordial coil transformers create a static output of energy. IF you are feeling frisky, buy yourself one and create your own power supply. It will solve your grounding problems forever. You'll need to source a transformer and possibly even chop the connector from your current one. Not many people like to do this, but it does work.
Second, check your laptop connector. IF you can you can even take a laptop power supply apart (essentially destroying it). Not a great thing, but if you look at the connector and the wiring straight into the transformer, you can see if it actually uses the ground lug or if it just has one on a typical cord. Often the manufacturer makes a proprietary trasnformer and cable just to be a pain in the butt. But some manufacturers use standard cords bought in bulk from a separate manufacturer to make it easier for you if you loose yours. Because the ground will be connected to the transformer createing the noise, but not created to the laptop. Any laptop that uses a round plug into the laptop does not use the ground, only the transformer. In which case its low risk to lift the ground .
Your laptop uses transformer which uses IC circuits to regulate the onflow current based demand from the laptop. This actually creates a very instable grounding and very definitley creates noise, especially in club environments which have lighting involved. Essentially a club technician will put lights on a separate line than sound. What they dont realize that a laptop DJ's laptop has the same behaviour as the lights so putting it on the sound line is actually a pretty bad thing.
Traditional tordial coil transformers create a static output of energy. IF you are feeling frisky, buy yourself one and create your own power supply. It will solve your grounding problems forever. You'll need to source a transformer and possibly even chop the connector from your current one. Not many people like to do this, but it does work.
Second, check your laptop connector. IF you can you can even take a laptop power supply apart (essentially destroying it). Not a great thing, but if you look at the connector and the wiring straight into the transformer, you can see if it actually uses the ground lug or if it just has one on a typical cord. Often the manufacturer makes a proprietary trasnformer and cable just to be a pain in the butt. But some manufacturers use standard cords bought in bulk from a separate manufacturer to make it easier for you if you loose yours. Because the ground will be connected to the transformer createing the noise, but not created to the laptop. Any laptop that uses a round plug into the laptop does not use the ground, only the transformer. In which case its low risk to lift the ground .
Posted Wed 31 Oct 07 @ 8:42 am
