lee eather
I am playing at a gig in a few weeks so i plugged in my speakers into the XLR outs on my mixer (djm600) and noticed whenever i open VDJ a fairly loud humming type sound commes from both speakers. The speakers have a slight idol humm anyway, but when i open virtual dj the sound triples and is very noticable and continues throughtout the songs, very notivable whne beat drops on in th emiddl eof the song.
I tried winamp and it was fine so iam wondering what it may be wit with virtual dj?
I tried winamp and it was fine so iam wondering what it may be wit with virtual dj?
Posted Fri 16 Nov 07 @ 12:40 am
Tear Em 'Up
Hi Lee, use the search feature for ground loop...I bet you find your answer there..good luck
Posted Fri 16 Nov 07 @ 12:47 am
djzare
lee eather wrote :
I tried winamp and it was fine so iam wondering what it may be wit with virtual dj?
I tried winamp and it was fine so iam wondering what it may be wit with virtual dj?
Vdj has a louder output then winamp does. Find a ground loop isolator.
Posted Fri 16 Nov 07 @ 1:37 am
jc5qns
I Had this same problem....I Hope this "Ground Loop Isolator" Works...Thanks....
JC
JC
Posted Fri 16 Nov 07 @ 2:00 am
lee eather
cheers for all the answers i shoulda searched :slap:
I found the sticky, it talks about using 2 prong adaptors at the power point, but say that it is unsafe and a ground loop isolator would be better.
It was talked in the sticky but not actually described what they were and where to go.
What would these look like and where would i attach it?
I found the sticky, it talks about using 2 prong adaptors at the power point, but say that it is unsafe and a ground loop isolator would be better.
It was talked in the sticky but not actually described what they were and where to go.
What would these look like and where would i attach it?
Posted Fri 16 Nov 07 @ 3:42 am
Tear Em 'Up
lee eather wrote :
What would these look like and where would i attach it?
Depends on where you live. US small, gray or orange, three holes on one end..two prongs on the other. UK/Europe..cant help you... They attach to the end of your power cord you pug into the wall. They eliminate the grounding connection.
Posted Fri 16 Nov 07 @ 3:55 am
Paz75
depends on the laptop power supply if lifting the ground is safe or not. ive seen laptops with no ground connection past the transformer and some with it. some laptops with metal chasis will zap you slightly if not grounded. the loop isolator is always the best way to go, but the ground lift trick is the easist. you can either use some masking tape on the ground lug for UK prongs, or buy a cheap power adapter that doesnt have it. just goto a radio shack or something.
Posted Fri 16 Nov 07 @ 6:11 am
lee eather
^^We'll mine has three prongs coming off the power connection so i say it does have earth. I live in Australia.
Are you saying that some laptops dont have earth from the transformer? Why? Doesnt this just mean that you've got more chance of getting zapped and should probably buy a a power chord that is earthed.
I think ill go the ground loop isolator option. There is a thread in the "selected guidlines" sticky about this if any1 is interested.
Are you saying that some laptops dont have earth from the transformer? Why? Doesnt this just mean that you've got more chance of getting zapped and should probably buy a a power chord that is earthed.
I think ill go the ground loop isolator option. There is a thread in the "selected guidlines" sticky about this if any1 is interested.
Posted Fri 16 Nov 07 @ 6:22 am
jimmy b
Sorry Paz,
but I life in the UK and my day job is a maintaince Engineer and I would not wrap masking tape around the earth prong of our plugs. It's there for a purpose and by doing that you may cause damage to your equipment or your health. It's a big fat NO.
Best just buy one.
Jimmy b
but I life in the UK and my day job is a maintaince Engineer and I would not wrap masking tape around the earth prong of our plugs. It's there for a purpose and by doing that you may cause damage to your equipment or your health. It's a big fat NO.
Best just buy one.
Jimmy b
Posted Fri 16 Nov 07 @ 6:26 am
lee eather
I had to ask, the sticky says to use the isolators inbetween the soundcard and mixer but wouldnt it be a good idea to isolate before the ground loop goes out to the soundcard. Say a isolator inbetween the laptop and power chord? Can you do it? I would'nt use the two prong adaptor idea due to the danger indicated.
Means i dont have to buy 2 isolators and two new RCAs as well.
Means i dont have to buy 2 isolators and two new RCAs as well.
Posted Fri 16 Nov 07 @ 11:59 am
TopHouse
I'm only going to say this one more time. In my younger days I was a fully qualified self employed electrician. I am also ex UK Royal Air Force electronics technician. I say this to give credibility to what I am going to say.
To the people that are advising others to remove electrical earths
Remember that your advice is going all over the world, where there are a whole range of electrical voltages, currents and configurations. Giving general advice to remove earths is total stupidity, is potentially not only dangerous but can kill!
Do NOT confuse an amplifier 'ground lift' switch with removing electrical earth/ground. They are NOT the same!
By all means, those who think they are clever doing this, carry on, but could you live with it if you advised someone to do this and they got electrocuted as a result?
To the people that are advising others to remove electrical earths
Remember that your advice is going all over the world, where there are a whole range of electrical voltages, currents and configurations. Giving general advice to remove earths is total stupidity, is potentially not only dangerous but can kill!
Do NOT confuse an amplifier 'ground lift' switch with removing electrical earth/ground. They are NOT the same!
By all means, those who think they are clever doing this, carry on, but could you live with it if you advised someone to do this and they got electrocuted as a result?
Posted Fri 16 Nov 07 @ 12:06 pm
jimmy b
I have to agree with Top House. I have seen first hand what damage Electricity can do,
and it it not a pretty slight I tell you that.
Jimmy b
Posted Fri 16 Nov 07 @ 4:43 pm
Paz75
to all you electrical engineers, this is not a 10000 volt lighting truss on industrial power pulling amperage in the 100s. its a simple 200watt, 12 volt, 3 amp onversion. no biggie. mind you it only takes 1.6 a at 10000 volt to paralyze someone for an hour, but lets not get into that. we all know what happens if you spill your beer in your laptop or drop the live transformer in the fish tank. just dont do it
a laptop uses dc power. we are not going to shatter ourselves or the world by removing the ground. anyhow, the UK has the most stringent power restrictions in the world, so a) congrats thats quite an achievement, b) you tend to be overparanoid.
ive seen laptop transformers blow up and its not a big thing. now if we were in a club and talking about the arrays of lighting and amps, this would be a different matter altogether.
second, the _proper_ reason why laptops are giving noise (i wrote this in some other thread) is because these days, laptop manufacturers try to cut down on weight. a main way to do this is in the transformer, so they no longer user those heavy ass tordial coils with a metal core. instead they use circuits that pull as much power as needed. these create massive irregularities including something that behaves like a ground loop, but technically is not one. im no engineer but have worked with people who know.
the surefire way to get rid of it is build your own power supply and use a toridal coil transformer. its grounded, its stable power, theres no noise.
me, i'll just continue using a lifted ground lug on my expensive laptop as i have done for years. maybe one day i'll break my soldering iron out of its dusty box and get on the net and find me a chunky transformer.
a laptop uses dc power. we are not going to shatter ourselves or the world by removing the ground. anyhow, the UK has the most stringent power restrictions in the world, so a) congrats thats quite an achievement, b) you tend to be overparanoid.
ive seen laptop transformers blow up and its not a big thing. now if we were in a club and talking about the arrays of lighting and amps, this would be a different matter altogether.
second, the _proper_ reason why laptops are giving noise (i wrote this in some other thread) is because these days, laptop manufacturers try to cut down on weight. a main way to do this is in the transformer, so they no longer user those heavy ass tordial coils with a metal core. instead they use circuits that pull as much power as needed. these create massive irregularities including something that behaves like a ground loop, but technically is not one. im no engineer but have worked with people who know.
the surefire way to get rid of it is build your own power supply and use a toridal coil transformer. its grounded, its stable power, theres no noise.
me, i'll just continue using a lifted ground lug on my expensive laptop as i have done for years. maybe one day i'll break my soldering iron out of its dusty box and get on the net and find me a chunky transformer.
Posted Fri 16 Nov 07 @ 4:46 pm
jimmy b
Have you seen someone die from a " just " a shock, No I don't think you have. I have and it stay's with you for a long time, and the smell.
It's not nice, so please stop giving info out like that.
Jimmy b
Posted Fri 16 Nov 07 @ 4:58 pm
Tear Em 'Up
Just order one of these...
http://www.pssl.com/Images/buttons/addToCartButton.jpg
That will work...and no one will die from its use.
http://www.pssl.com/Images/buttons/addToCartButton.jpg
That will work...and no one will die from its use.
Posted Fri 16 Nov 07 @ 4:59 pm
jimmy b
Sorry about getting on my Soap Box.
Just follow TearEmUp good advice.
Jimmy b
Posted Fri 16 Nov 07 @ 5:02 pm
Paz75
jimmy, i can respect your feelings mate, i have also seen someone die in similar circumstance. however, can you describe the means of how it happened? I highly doubt it was at the hands of a laptop transformer. there are battles to be fought in the name of good practice, but i doubt this is one of them.,..
this is also coming from a nut who's taken 110 volt wires and stuck them to his tongue... it wasnt such a big deal, i doubt 240 is life-threatening. keep in mind my discalimer was that this isnt a 10000 volt lighting truss.
this is also coming from a nut who's taken 110 volt wires and stuck them to his tongue... it wasnt such a big deal, i doubt 240 is life-threatening. keep in mind my discalimer was that this isnt a 10000 volt lighting truss.
Posted Fri 16 Nov 07 @ 8:50 pm
Paz75
incidentally i've also seen someone loose his finger from a shop-lathe because he thought he didnt need to remove his wedding ring (actually he was too fat to take it off) and it caught on a burr. next thing, finger was splattered against the adjacent wall.
long story short, i agree. take any advice with a certain amount salt. some people are seriously misinformed. but i dont feel myself to be one of them.
long story short, i agree. take any advice with a certain amount salt. some people are seriously misinformed. but i dont feel myself to be one of them.
Posted Fri 16 Nov 07 @ 8:54 pm
Paz75
anyhow, last one from me, there is another solution. using a DI (direct injection) box or cable will help. basically it's adding a transformer in the audio chain. its not a great idea because it affects the sound quality, but a low enough induction level changes the sound only nominally and achieves the solution of getting rid of a buzz.
but on that respect, here is some alternate advice off the net:
There's another source of noise, and it has nothing to do with ground loops, and it's incredibly common with laptops.
DC offset.
Laptops run on DC, and the power supplies for them are often fairly lousy switching supplies, so they're running on noisy DC. This often leaks out onto analog ports, and causes buzzing noises.
The way to tell, since you are a musician: Does the noise have tone, if so, how close to 60Hz or a harmonic is it?
If it is that, then it's AC hum, and a ground loop. Normally, you hear the 120Hz harmonic (100Hz for you euro folks.)
However, I'm willing to bet it isn't -- instead, it's DC hash from the power supply. The reason you don't hear it on battery is that batteries put out very pure DC.
If the laptop is actually generating sound, what you need to solve the problem is an isolation transformer. Many DIs are also isolation transformers, but not all. A transformer will pass the AC signal that has your music, but is a solid wall to DC, thus, the DC hash doesn't happen.
If the laptop is just generating control signals, something as simple as an inline capacitor can fix it. The problem with that in the audio chain is that it'll act as a filter, when combine with the various components in the audio output, will seriously change the sound of the output, which you don't want. But for control circuits, the frequency bandwidth often isn't critical. Ideally, though, for digital signals, you'd use an opto-isolator, which uses an LED and a photo transistor to completely isolate the two circuits.
If you want to check for DC hash before dropping money on parts, that's simple, if you're comfortable with a little cable hacking. We just use a cheaper DC blocker. You'll need a cable you can sacrifice (or wanted to shorten) and two or three AC capacitors (namely, not normal electrolytic or tantalum caps.) Cut the cable, and solder in a cap to reconnect each wire, matching the color. Make sure they don't short to each other. Now, use that from the output of the notebook to your mixer and beyond, plug in the notebook, and listen.
If the noise goes away, you've got a DC hash problem. Alas, with cheap caps, most of the musicality of the output will be gone as well, but now you know you need to isolate the DC out of chain, namely, you need an isolation transformer. Note that cheap ones will cause the same sorts of musicality problems, and the component ones that Radio Shack sells are optimized for phone/ham use, and only pass 300-3Khz. Great for phone, lousy for music.
If it doesn't, then it is AC noise, and you need to look at ground loops and other strangeness. But given that, with a notebook, you're effectively isolated from ground anyway (most notebooks don't even have grounding plugs), I'm betting DC hash.
(Note: I spent 10+ years doing live sound work, and many more interfacing computers and radios. Both have the same issues with bad supplies putting out noise on DC.)
but on that respect, here is some alternate advice off the net:
There's another source of noise, and it has nothing to do with ground loops, and it's incredibly common with laptops.
DC offset.
Laptops run on DC, and the power supplies for them are often fairly lousy switching supplies, so they're running on noisy DC. This often leaks out onto analog ports, and causes buzzing noises.
The way to tell, since you are a musician: Does the noise have tone, if so, how close to 60Hz or a harmonic is it?
If it is that, then it's AC hum, and a ground loop. Normally, you hear the 120Hz harmonic (100Hz for you euro folks.)
However, I'm willing to bet it isn't -- instead, it's DC hash from the power supply. The reason you don't hear it on battery is that batteries put out very pure DC.
If the laptop is actually generating sound, what you need to solve the problem is an isolation transformer. Many DIs are also isolation transformers, but not all. A transformer will pass the AC signal that has your music, but is a solid wall to DC, thus, the DC hash doesn't happen.
If the laptop is just generating control signals, something as simple as an inline capacitor can fix it. The problem with that in the audio chain is that it'll act as a filter, when combine with the various components in the audio output, will seriously change the sound of the output, which you don't want. But for control circuits, the frequency bandwidth often isn't critical. Ideally, though, for digital signals, you'd use an opto-isolator, which uses an LED and a photo transistor to completely isolate the two circuits.
If you want to check for DC hash before dropping money on parts, that's simple, if you're comfortable with a little cable hacking. We just use a cheaper DC blocker. You'll need a cable you can sacrifice (or wanted to shorten) and two or three AC capacitors (namely, not normal electrolytic or tantalum caps.) Cut the cable, and solder in a cap to reconnect each wire, matching the color. Make sure they don't short to each other. Now, use that from the output of the notebook to your mixer and beyond, plug in the notebook, and listen.
If the noise goes away, you've got a DC hash problem. Alas, with cheap caps, most of the musicality of the output will be gone as well, but now you know you need to isolate the DC out of chain, namely, you need an isolation transformer. Note that cheap ones will cause the same sorts of musicality problems, and the component ones that Radio Shack sells are optimized for phone/ham use, and only pass 300-3Khz. Great for phone, lousy for music.
If it doesn't, then it is AC noise, and you need to look at ground loops and other strangeness. But given that, with a notebook, you're effectively isolated from ground anyway (most notebooks don't even have grounding plugs), I'm betting DC hash.
(Note: I spent 10+ years doing live sound work, and many more interfacing computers and radios. Both have the same issues with bad supplies putting out noise on DC.)
Posted Fri 16 Nov 07 @ 9:03 pm
A Man and His Music
I always lick the plug just before I push it in, but I am a professional, so PLEASE DO NOT TRY THIS AT HOME. My lawyer said I had to put that in.
Posted Fri 16 Nov 07 @ 9:27 pm
