Loud humming when I connect my DVD player


to my preamp via RCA connections. Otherwise, my system is dead silent. Its power cord has no ground wire. Any suggestions?
rockadanny
Your interconnects may have a broken ground. Have you tried another pair? Are the DVD prayer and Preamp plugged into the same outlet? If not: One outlet may be wired incorrectly, with regard to hot and neutral. Try reversing the phase on the DVD player(flip the plug in the socket).
I assume the DVD player is connected to a TV....
Is the TV connected to a CATV system? If so you are experiencing a ground loop. Disconnect the incoming CATV coax cable from the cable box and then check for hum.
Post back results of test.
Tried all but nothing worked except disconnecting the TV from the CATV box. So either the box or the cable is the issue. Anything I can do about this?
The earth connection of the grounding block for the CATV Coax cable shield is causing the problem.There is a difference of potential, voltage, between the CATV earth ground and the main electrical grounding system of your home.

Buy one of these and install it between the incoming CATV cable coax and the cable box.

You also could try cleaning and re-terminating the ground wire on the grounding block. The grounding block should be located on the outside of your house where the cable company's coax cable connects to the outside of the house. Sometimes the block is inside a box, sometimes just exposed on the outside of the house.

Clean both ends of the ground wire and re-terminate.
The other end of the ground wire from the grounding block should connect to the main grounding system of your home. Not a separate ground rod only. A separate isolated ground rod connection will cause a ground loop condition as well as a lightning hazard for your audio and TV equipment.
Jea48 - Cool! I will do as you suggested and report back. Thank you Rodman and Jea!
Your friendly electrician can check ground using a 'megger'.
Jea48,
Did as you suggested and picked up a Jensen cable TV ground isolater ($59 + ship). Worked! No more hum! Thank you!
Rockadanny,

Thanks for posting the cable ground isolator solved your problem.
Jim
I used this product to suppress hum from directv hum with sat cable. When I placed Jensen between coax and sat receiver, it reduced hum 80%, but it failed to pass sat signal, kept getting 'searching for sat signal' error. What works for sat signal hum, new problem since added marantz 7005 processor into rig, never had hum before. Help, please
new problem since added marantz 7005 processor into rig, never had hum before.
??
Marantz does not use the safety equipment ground....
??

The Jensen isolator will not work on a SAT system. Says so in the lit......

If your problem is a ground loop you will need to find the grounding block for the SAT coax incoming cable. Once you find the grounding block, for a test, disconnect the ground wire from the block. (The ground wire will more than likely be a copper #14 awg.) Go in the house and check for the hum. No hum you have a ground loop problem...

No hum... Go back outside and trace out where the ground wire from the ground block goes and connects to.

I have a feeling it connects to a dedicated ground rod outside. If that is the case you will need to check the distance from the ground block to the main earth grounding system of your home.

If the distance is less than 25ft run a new #12 awg solid copper ground wire from the ground block to the main earth grounding system of your home and connect it there. (The dedicated ground rod will no longer be used.)

If the distance from the SAT ground block to your homes earth grounding system is greater than 25ft then you will need to run a #6 copper ground wire from the dedicated ground rod to your homes main earth grounding system.
Clean the connection at the ground block and ground rod and reconnect a #12 copper wire from the block to the ground rod.

Post back your results or any other questions you may have.
Dear Jim; thanks for your thoughtful and thorough response. silly question: how do I identify the ground block on my Satelite dish cable system; and where might it be? What does it look like? Is it where the 14g cooper ground wire is coming out of? Where would the main grounding block be for the electrical service panel coming into the house? thanks again...hard to believe I have no knowledge of this stuff; but ask me about tubed vs solid state, vs digital vs music servers; that I have opinions on; not how the electricity and grounds can screw up my expensive rig...
silly question: how do I identify the ground block on my Satelite dish cable system; and where might it be? What does it look like? Is it where the 14g cooper ground wire is coming out of?

Mribob,

In most cases the ground block is mounted outside just before the coax cable/s enter the house. But not always.... If the house has a basement some SAT installers will mount the block inside where the coax cable/s enter the basement. For those mounted in the basement I have seen the ground block wrongly connected to a nearby domestic cold water pipe. By NEC code it should connect to the main electrical grounding electrode system of the premises.

Example of a ground block
http://www.sadoun.com/Sat/Order/Install/Grounding.htm

The ground block has a hole with a set screw for the termination of the ground wire. NEC says the minimum size be #14 awg so that is usually what is used. I would use at least #12 for a short distance. Maybe a #10 awg copper for 20ft to 25 ft.

Where would the main grounding block be for the electrical service panel coming into the house?

There is not a block per say.... The grounding electrode system for the main electrical service can be a combination of earth ground connections depending on how old your home is and local codes as well as requirements of the power utility company.

The earth ground may be an outside driven ground rod/s. It could be a metallic incoming water line from outside. If built in the 70s or newer good chance it has both. If the house has an incoming matallic domesic water line that is alway an earth ground connection. (Grounding Electrode)

If the main electrical panel is exposed in the basement that is good place to start for a good ground connection location.

Look around the outside of the panel enclosure. Look for a bare #6 or #4 copper wire. You might see 1 or 2, maybe 3 if the house is new. This or these ground wires go to and connect to the earth, Grounding Electrode/s.

You will need to go to Home Depot, or other, and buy an electrical split bolt.

Clean the area where you can install the split bolt with some medium grit sand paper. This will be the connection for the SAT ground block ground wire.

If you are lucky and the SAT installer did the install right and connected the SAT ground block wire to the main electrical panel earth grounding system. (It does not have to be connected where I suggested. It can connect anywhere in the grounding electrode wiring system.) The problem could be nothing more than a loose or corroded connection at one end or the other or both... Break down, clean and tighten the connections.

(I prefer the connection as close to the electrical panel earth connection as possible. Less chance for a ground loop problem.)

LOL, I tried to keep it simple.... Looks pretty long....
Post back results or questions....
Jim; great response; you must have an electrical background; appreciate your knoweldge. I will call my electrician who ran my dedicated 20amp lines; and have him help me; don't have a tall enough ladder for Satelite; nor do i feel comfortable performing these things on my own; more after I get help and attempt fix.
Happy Thanksgiving..hopefully no more humming...