Fix ground loop - Mackie SRM-450 System

get a tuneup.
or scan it for loose of closed loop operation, (USA CARS)
at idle
at flat ground cruise, right foot steady.
if CLose loop fails we fix that first. ask.

Hi You have a ground loop problem. Rolling shaded bars are the classic sign of a ground loop. Your TV & AV gear are likely not on the same
ground level as the input cable line. The cable line is likely floating
to a different ground. But this is not hard to fix.

check other inputs AVI, HDMI,,

do you here the hum on all inputs?

The hum maybe from a bad ground loop,, unplug all pluged in inputs, [dvd,games,radio,ect] <--check for hum.

If the hum is gone, plug inputs back in one at a time and test,,

When you find the source of the hum, go get a ground loop isolator to fix.

We can only guess what the input port might be a part of... Computer? Digital recorder? who knows...

You LIKELY have a ground loop. Use isolation techinque to eliminate ground loop. Tools for that often include what is known as a "DI" or direct input box. It often has an isolation transformer in it to break the ground loop. You use or set the DI to "ground lift".

donkandrun

In regards to the sound that you are hearing it is most likely one of 2 things, ether a ground loop or bus noise. This will take testing on your part to see where the issue is.

First we will cover the most likely which is a ground loop. I included a link below that covers it in more detail if you would like to read it. For the most part you have a device that is connected to you computer grounding out through the computer. Which is fine and happens all the tiime with electronics. The reason why you hear the sound is the path to ground is going through the sound card causing an induction on the sound card causing the sound you hear. So the easy way to find out for sure is unplug all devices from the computer except for your monitor and speakers. If the sound goes away then most like this is what your issue was.

To fix it you will need a ground loop isolator for that device. What this does is reroute the ground signal so it does not ground through your computer/audio equipment. Note this is the same thing that can happen with your home recevier too.

Ground Loop
http://en.wikipedia.org/wiki/Ground_loop_(electricity)

The other issue witch is remote is that you have bus noise. It is kinda of the same effect but a totally different cause. Sometimes if you get to much data traveling on a data bus circuit it will cause the same induction causing the noise. However since you have a Dell it is remote that this is the issue unless you added a card internally to the computer and/or added a hefty USB device to the system. The devices may have not been tested with this system. On the other side this might me an issue with the motherboard as well. So it would not hurt to call Dell support if it is not a ground loop issue.

Hope this helps

Issken

i once installed spark plug resistors (arrestors) that are supposed to help

younhave a bad groun. A ground wire should be same size as power (gage) wire and NO longer than 1 foot.

This is usually indicative of a ground loop causing noise from the vehicle electrical system. Long story short your stereo isn't grounded well enough.

There are two possible solutions:

1. Ground all components to the same point. This will reduce the potential and should greatly reduce any noise.

2. If number 1 is not possible (and it often is not), use a "ground loop isolator", available at nearly all electronics stores, or car audio suppliers. This device prevents a direct electrical connection between the two sources and will usually fix the ground loop.

Sounds like you need a ground loop transformer for each camera. You can get one a electronics shop. Just ask for a ground loop transformer. Connect it inline between the camera and where it's terminated. This will fix you.

If this is seen when you are connecting to a cable box or satellite box like DirecTV through or other such device your issue is most likely a DC ground loop. Here are some suggestions:
Video Projector ground loop
1) If you have horizontal hum bars when your projector is connected to a set-top box or other equipment that are on a different circuit or are grounded causing a ground potential between the source and the projector
2) Hum bars are the result of a ground loop, usually caused by cable television that has not been properly grounded
Try this to verify:
1) Disconnect your cable television coax from the wall by unscrewing it.
2) Run your Projector and verify that you are no longer getting the lines.
If you have verified that the issue was a ground loop by testing the solution requires a DC
Ground Blocker style device similar to the below options:
1) Go to http://www.cablesandconnectors.com/02100-02.HTM (part number 2118)
2) Purchase a DC GROUD BLOCKER & ISOLATION TRANSFORMER either from the above or similar electronics store location.
3) Other examples and ground loop explanations for both Video & Audio can be found at the following link for information about ground loop; scroll to Why Ground Loop is a Problem:
http://www.epanorama.net/documents/groundloop/index.html
4) Other commercial antenna signal isolators are available on the web or simply see your local Radio Shack
5) Connect the isolator device chosen to your set-top box and hook it back up.
You will be back-up and running in no time.