humming sound????

[ryan4blu]

Hey guys, got a question. have a friend that has a panny plazma and a onkyo 606 receiver and he is getting a humming noise when you plug in the hdmi cable from the tv to the receiver. any thoughts? maybe a ground problem? not sure. we changed the hdmi cable and tried one of mine and it still hums. its seems it comes between the receiver and the tv? any help would be great. thanks

[Blu-Dog]

Originally Posted by ryan4blu

Hey guys, got a question. have a friend that has a panny plazma and a onkyo 606 receiver and he is getting a humming noise when you plug in the hdmi cable from the tv to the receiver. any thoughts? maybe a ground problem? not sure. we changed the hdmi cable and tried one of mine and it still hums. its seems it comes between the receiver and the tv? any help would be great. thanks

Definitely a ground loop problem.

Step 1: make sure the two units are plugged into different outlets.

Step 2: Make sure the power and HDMI lines are separated - don't put them next to each other.

Also, see if any other source causes humming too. CD player, cable/satellite box, all that. Try one at a time, see what happens.

[Phil Taylor]

I was thinking that you would want them plugged into the same circuit so there would be no difference in ground - no?

[phansson]

Sounds like a ground loop problem. Usually, the easiest way is to remove the ground plug. You can also try a 3 plug to two plug adapter. You can usually pick these up at any hardware store.

You can also try to plug it into another outlet and see if the humming stays.

[Blu-Dog]

Originally Posted by Phil Taylor

I was thinking that you would want them plugged into the same circuit so there would be no difference in ground - no?

It's a reasonable test, but sometimes the problem is in the circuit itself - not what's plugged into it. I had a faulty Ground Fault Interrupter (GFI) socket, caused me untold grief until I figured it out.

[VinnAY]

Originally Posted by Phil Taylor

I was thinking that you would want them plugged into the same circuit so there would be no difference in ground - no?

Correct, the person above either typo'd or is wrong. Little outlet tester's are available for about $5 from your local hardware store, they'll indicate just by plugging the device in if your outlet is wired properly.

[ryan4blu]

thanks for all your input. we switched hdmi cables from the cable box to the receiver and it seems it went away? we shall see how it goes.

thanks again

[sheedoe]

It could be ground loop from the coax cable that connects to the cable box. I used to get humming from my speakers. Then I found this that took care of the problem.

[VinnAY]

Originally Posted by sheedoe

It could be ground loop from the coax cable that connects to the cable box. I used to get humming from my speakers. Then I found this that took care of the problem.

Ground your cable entrance to the house for free. If you have just a little know how, better than $45.

[sheedoe]

Originally Posted by VinnAY

*Ground your cable entrance to the house for free.
**If you have just a little know how, better than $45.

"Ground loop issues with television coaxial cable can also affect any connected audio devices such as a receiver. Even if all of the audio and video equipment in, for example, a home theater system is plugged into the same power outlet, and thus all share the same ground, * the coaxial cable entering the TV is actually grounded at the cable company. The potential of this ground is likely to differ slightly from the potential of the house's ground, so a ground loop occurs, causing undesirable mains hum in the system's speakers. ** A cheap way to resolve this problem is to buy a 75-Ohm Coax Combiner-Splitter and a "Matching Transformer". The 75-Ohm Coax Combiner/Splitter converts the impedance from 75 ohms to 300 ohms and the "Matching Transformer" converts the impedance from 300 ohms to 75 ohms. Both parts connected together will act as a "poor man's" isolation transformer."
-wikipedia