[Niteshade]

I have never had a ground loop issue...with anything.

If you have had a ground loop problem, what did you do and what was the supposed cause?

[john1970]

I had grounding loops between my AV Receiver and my amp using the pre-amp outputs on the AV Receiver.  My solution was to purchase Isomax Audio Isolation Transformers from Jensen Transformers.  Although a bit expensive, they solved the problem and are built to professional standards here in the USA.

Best,

John

[bunnyma357]

The most common cause is an AV system with 2 grounds the electrical system ground and a signal ground for the cable/satellite feed. The problem will most often show up in a subwoofer, since the hum is at 60 Hz, even though the sub isn't the problem.

Other common causes are electrical wiring that has been grounded to pipes combined with wiring that has a proper ground at the electrical box. Also any piece of equipment that combines systems that have different grounds (phone/cable/electrical) may cause issues. So grounding issues are more common now that everything is interconnected - your modems, cableboxes, routers, computers, etc. - are all likely to be connecting separate grounding systems.

When I used to do installation work for large TV Post-production facilities, ground loops were a major concern, since you had very complex systems, all interconnected. In the best designed facility I worked at, they used a method while wiring and construction were occurring to find ground faults that was simple and effective.

The ground for the equipment system was lifted at the electrical box and a smoke detector was connected between the building electrical ground and the equipment grounding system. If a ground fault occurred connecting the 2 separate grounds the alarm would go off and we would have to run around the facility trying to figure out the cause. 

Over 6 months of installation, the alarm went off probably once a week for lots of different causes - a drywall screw through a metal stud penetrates a signal cable, the insulation on a cable gets scraped and the shield contacts a pipe, etc.

After that experience I figured that most houses have several built in ground faults from when they were constructed, or upgraded - It's just luck of the draw whether they'll effect your equipment.


Jim C

[Dan Banquer]

I had grounding loops between my AV Receiver and my amp using the pre-amp outputs on the AV Receiver.  My solution was to purchase Isomax Audio Isolation Transformers from Jensen Transformers.  Although a bit expensive, they solved the problem and are built to professional standards here in the USA.

Best,

John

Hopefully the moderator here will put this post up as a "sticky" for all to see as this is the proper way to address a ground loop for consumers.
Regards;
     Dan Banquer

[Niteshade]

Ground currents are strange beasts. 

I run into similar situations with large metal surfaces. One point can be noisy and one within a few inch radius will be quiet. Talk about being bedeviled! Star grounding helps, but doesn't always completely solve the issues.

The moral is: Sometimes you have to hunt for quiet spots to obtain a quiet ground.

[ctviggen]

I had grounding loops between my AV Receiver and my amp using the pre-amp outputs on the AV Receiver.  My solution was to purchase Isomax Audio Isolation Transformers from Jensen Transformers.  Although a bit expensive, they solved the problem and are built to professional standards here in the USA.

Best,

John

Hopefully the moderator here will put this post up as a "sticky" for all to see as this is the proper way to address a ground loop for consumers.
Regards;
     Dan Banquer

I'm not sure about that, Dan.  I had a hum in my sub that was not solved by a Jensen transformer.  One hum was solved by switching the phase of the outlet to the same phase as the other equipment.  Another hum was solved by replacing interconnects.  The latter one took a long time to debug; I basically had to take apart my system until there was no hum.  I pulled off the interconnects, and the hum disappeared.  I put on different interconnects and no hum.  Certainly, Jensen transformers should work in many cases.

The first thing I would do is ensure that your earth ground is correct and that your outlets are correctly wired and grounded.  Then, I'd start with the most simple system -- an amp through speaker wires to the speakers. No input on the amp.  Then add one thing in at a time until you get the hum.  If you can use balanced interconnects, use those instead of unbalanced. 

[ctviggen]

Oh yeah, and ground the satellite/cable connection to your earth ground.  Everything should be grounded at that one point (or wire run to that point that at least meets NEC requirements). 

[Dan Banquer]

Oh yeah, and ground the satellite/cable connection to your earth ground.  Everything should be grounded at that one point (or wire run to that point that at least meets NEC requirements).

Hi Bob;
   All of this has been discussed at length in this forum, as well as written on other web sites such www.audioholics.com and more than a few textbooks.
In addition you may wish to search for the thread I did many years ago on the Lab forum titled "Grounding Practices in Consumer Audio"
John1970's post is very typical of the types of problems found and I still without reservation recommend it as a "sticky" for this forum.
As for me I do not have the luxury of time to discuss theory and practice in this venue.
My apologies and best of luck to all of you.
d.b.