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#1
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Ground loop?
Do you have everything plugged into a powerbar/surge protector on one wall
socket?,If not this can cause the hum.You want everything on one powersupply.A power conditioner would help also. Jon Myatt wrote in message .. . I have what appears to be a ground loop, and it's driving me *mad*. My S90 keyboard is plugged into my ST Audio DSP24 C-Port sound card (well, rack). The balanced outputs of the DSP24 then go to the power amp. When the S90 is connected I hear a constant whirring in the background, which gets worse if I move the mouse. Disconnecting the S90 makes it go away. I've tried about five different pairs of jack-jack leads - all the same. Other devices plugged into the DSP24 are fine. The S90 plugged into the power amp directly is fine. Any suggestions? I'm tempted to ditch the DSP24 and buy a Motu or M-Audio... Thanks, Jon. Remove the obvious from my address to mail me. Thanks. |
#2
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Ground loop?
It could also be caused by power cables crossing over patch cables or even
be caused by something sitting to close to a power supply or amp in a rack. Jon Myatt wrote in message .. . I have what appears to be a ground loop, and it's driving me *mad*. My S90 keyboard is plugged into my ST Audio DSP24 C-Port sound card (well, rack). The balanced outputs of the DSP24 then go to the power amp. When the S90 is connected I hear a constant whirring in the background, which gets worse if I move the mouse. Disconnecting the S90 makes it go away. I've tried about five different pairs of jack-jack leads - all the same. Other devices plugged into the DSP24 are fine. The S90 plugged into the power amp directly is fine. Any suggestions? I'm tempted to ditch the DSP24 and buy a Motu or M-Audio... Thanks, Jon. Remove the obvious from my address to mail me. Thanks. |
#3
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Ground loop?
"Jon Myatt" wrote in message .. . I have what appears to be a ground loop, and it's driving me *mad*. My S90 keyboard is plugged into my ST Audio DSP24 C-Port sound card (well, rack). The balanced outputs of the DSP24 then go to the power amp. When the S90 is connected I hear a constant whirring in the background, which gets worse if I move the mouse. Disconnecting the S90 makes it go away. I've tried about five different pairs of jack-jack leads - all the same. Other devices plugged into the DSP24 are fine. The S90 plugged into the power amp directly is fine. Any suggestions? I'm tempted to ditch the DSP24 and buy a Motu or M-Audio... If none of the other suggestions work, just use a ground lift and forget about it. They cost a dollar or so. It's just an adapter that goes from 3-prong to 2 prong...thus removing the ground. I don't reccomend doing this to everyone for all situations...but it sounds like this would work for you just fine. |
#4
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Ground loop?
That doesn't sound like a ground loop, which is electricity related, it sounds more like interupt problems. Will run it past my engineer friends. -- Boulton ------------------------------------------------------------------------ Posted via MIDIBuddy - Professional MIDI Files and Music Community http://midibuddy.net View this thread: http://board.midibuddy.net/t63246.html |
#5
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Ground loop?
I have had a similar problem in the past with a different set of hardware.
Try lifting the sheild on the balanced audio connections. This worked for me. Rob "Jon Myatt" wrote in message .. . I have what appears to be a ground loop, and it's driving me *mad*. My S90 keyboard is plugged into my ST Audio DSP24 C-Port sound card (well, rack). The balanced outputs of the DSP24 then go to the power amp. When the S90 is connected I hear a constant whirring in the background, which gets worse if I move the mouse. Disconnecting the S90 makes it go away. I've tried about five different pairs of jack-jack leads - all the same. Other devices plugged into the DSP24 are fine. The S90 plugged into the power amp directly is fine. Any suggestions? I'm tempted to ditch the DSP24 and buy a Motu or M-Audio... Thanks, Jon. Remove the obvious from my address to mail me. Thanks. |
#6
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Ground loop?
"Dale Farmer" wrote in message ... area242 wrote: "Jon Myatt" wrote in message .. . I have what appears to be a ground loop, and it's driving me *mad*. My S90 keyboard is plugged into my ST Audio DSP24 C-Port sound card (well, rack). The balanced outputs of the DSP24 then go to the power amp. When the S90 is connected I hear a constant whirring in the background, which gets worse if I move the mouse. Disconnecting the S90 makes it go away. I've tried about five different pairs of jack-jack leads - all the same. Other devices plugged into the DSP24 are fine. The S90 plugged into the power amp directly is fine. Any suggestions? I'm tempted to ditch the DSP24 and buy a Motu or M-Audio... If none of the other suggestions work, just use a ground lift and forget about it. They cost a dollar or so. It's just an adapter that goes from 3-prong to 2 prong...thus removing the ground. I don't reccomend doing this to everyone for all situations...but it sounds like this would work for you just fine. Removing the power cord safety ground connection is a dangerous practice that one should not do unless you are willing to risk your life and the life of the eight year old daughter of the big name that is touring your studio for consideration of recording his next platinum album. That's a little extreme. It's not a great thing to make a habbit of, as it is risky mostly for your GEAR in case of a major power surge. Also, based on the set up he described, I don't get the impression we're dealing with a ton of gear in a major studio. So, I would say that the platinum recording artist and his daughter are safe as well. I've done this several times over the years...mainly just to verify that I am in fact dealing with a ground loop issue, and to then identify the source of it. You are free to do it, but you do have to accept the consequences of tampering with safety systems. If you do have to break a ground connection in the system to open a ground loop, break it on a signal cable. Are all the systems plugged into the same wall outlet or power strip? Is the safety ground wire intact all the way to you building ground point? Are there other systems in close physical proximity that may be radiating EMI? Based on your description, I'll take a bit of a guess and say that the problem is actually inside your computer. Computers are full of RF trash radiating around inside of them. Open up the computer and carefully examine all the faraday shielding of the case. Look for fingers bent, contacts corroded or losing their springiness, holes in the case, etc. Examine the sound card carefully, Look at the shielding around the analog portion of the card, particularly where the connectors are soldered to the board. Cracked or cold solder joints are a possibility, or a damaged card from a too vigorous insertion or removal of a cord connector. What has recently been changed on the computer? New fan, power supply, monitor, software? Look at all the cords and check for damage. Unplug and replug all the connectors to clean off corrosion buildup. --Dale |
#7
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Ground loop?
area242 wrote:
That's a little extreme. It's not a great thing to make a habbit of, as it is risky mostly for your GEAR in case of a major power surge. Also, based on the set up he described, I don't get the impression we're dealing with a ton of gear in a major studio. So, I would say that the platinum recording artist and his daughter are safe as well. I've done this several times over the years...mainly just to verify that I am in fact dealing with a ground loop issue, and to then identify the source of it. There's the catch... If you really do understand power and grounding you are probably not going to ask the question. If you are asking the question you may not understand power and grounding, and you might assume that lifting the safety ground solved your problem, and leave it lifted. I too have been known, every once in a while, to use a cheater to prove a loop exists. It is quick and easy (aka lazy)! But I am careful never to do it if someone watching might assume it is the solution instead of a troubleshooting tool. I think it is a very good practice to dissuade folks from breaking a safety ground to solve a ground loop. It is a much better practice to advice them on the safe way to fix the problem. I'm not arguing with your logic here... just your conclusionG! Bill |
#8
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Ground loop?
"Bill Thompson" wrote in message ... area242 wrote: That's a little extreme. It's not a great thing to make a habbit of, as it is risky mostly for your GEAR in case of a major power surge. Also, based on the set up he described, I don't get the impression we're dealing with a ton of gear in a major studio. So, I would say that the platinum recording artist and his daughter are safe as well. I've done this several times over the years...mainly just to verify that I am in fact dealing with a ground loop issue, and to then identify the source of it. There's the catch... If you really do understand power and grounding you are probably not going to ask the question. If you are asking the question you may not understand power and grounding, and you might assume that lifting the safety ground solved your problem, and leave it lifted. I agree...he should keep in mind that his ground loop problem isn't "solved" as much is as it is just identfied. I didn't mean to suggest that he really consider it solved and forget about it. I just meant that he would then know, without a doubt, that he was dealing with a ground loop and where it is. I too have been known, every once in a while, to use a cheater to prove a loop exists. It is quick and easy (aka lazy)! But I am careful never to do it if someone watching might assume it is the solution instead of a troubleshooting tool. Yep, same here. I think it is a very good practice to dissuade folks from breaking a safety ground to solve a ground loop. It is a much better practice to advice them on the safe way to fix the problem. Yes, I agree that they should be dissuaded from using it to "solve" a ground loop. But, I see no harm in people knowing a quick way to identify and confirm that they are dealing with a ground problem. I'm not arguing with your logic here... just your conclusionG! Yeah, I understand what you mean...my original post sounded as though it was a problem solved kind of thing...I think it's miscommunication, as I meant "problem solved" in the sense that he would know for sure he had a ground loop problem and where it was. I forget that not everyone knows about the purpose of grounding...and the potential problems with breaking the ground permanently. That said, I still suggest he use one to confirm that he is really dealing with a ground loop, and to identify it's source. |
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