Hello, I have a bizarre trouble...
I have a gainclone at home and it work very well on my speaker at home. This week, I tried my gainclone with my friend system and it make a loud hum.....
I don't undertand, maybe because de "cheap" dvd player of my frind doesn't have ground ??
Maybe the speakers are two sentisive ???
With nothing at the input, it make no noise, when I plug the dvd player, the noise apper.
Do you know the problem ??
I have a gainclone at home and it work very well on my speaker at home. This week, I tried my gainclone with my friend system and it make a loud hum.....
I don't undertand, maybe because de "cheap" dvd player of my frind doesn't have ground ??
Maybe the speakers are two sentisive ???
With nothing at the input, it make no noise, when I plug the dvd player, the noise apper.
Do you know the problem ??
Connect the two (amp and DVD) in the same power outlet and see if the hum still there. Something to do with the GND loops.
Is the DVD connected to a TV? Where is the TV connected to? Disconnect the TV from the DVD player.
/Greg.
Is the DVD connected to a TV? Where is the TV connected to? Disconnect the TV from the DVD player.
/Greg.
Yes, the video output of the DVD player is in the TV, and the audio output is in the gainclone.
This can cause a problem ???
This can cause a problem ???
This was the problem! The noise leave when I disconnect the video cable.
But, How I can listen a movie??? If a plug the video cable, I have a big hum in the speakers and if I don'T plug the video cable, I don'T have image !!!!!!
The TV doesn't have any gound. The power cord of the TV have only 2 pin.
How can I repear this problem ???
Thank you !!!
But, How I can listen a movie??? If a plug the video cable, I have a big hum in the speakers and if I don'T plug the video cable, I don'T have image !!!!!!
The TV doesn't have any gound. The power cord of the TV have only 2 pin.
How can I repear this problem ???
Thank you !!!
The TV doesn't have any gound. The power cord of the TV have only 2 pin
That's right but the TV is grounded thru the antenna cable. You can by an isolation trafo to either the antenna cable ore the audio (2)
That's right but the TV is grounded thru the antenna cable. You can by an isolation trafo to either the antenna cable ore the audio (2)
If you do a search on "ground loop" you will come across many suggestions and examples of fixes. You will possibly need to buy or make yourself an isolation transformer for the cable connection.
AC devices are grounded even through a 2 pin plug. That's why it's important to not mix white wires and black wires.
AC devices are grounded even through a 2 pin plug. That's why it's important to not mix white wires and black wires.
dalbjerg said:
No, that's misleading. The TV is grounded through the 2 pin plug AND the video cable. If it wasn't, there would be no loop. It's why the white wire is white and the black wire is black (or blue and brown overseas).
Disconnect the TV antenna. Does the hum go away?
I have been able to break the ground loop in cases such as this by opening the shield of the TV antenna cable and connecting a couple of 100 pf capacitors across the break. This breaks the loop at audio frequencies but permits RF to pass.
I have been able to break the ground loop in cases such as this by opening the shield of the TV antenna cable and connecting a couple of 100 pf capacitors across the break. This breaks the loop at audio frequencies but permits RF to pass.
The TV is grounded through the 2 pin plug
I’m sorry too tell you that in the whole EU no TV is connected galvanic to ground thru the 2 AC wires. That will mean that you could have 230Vac (110V ) on the chassis. That would mean that you would actually touch the Powerline on the antenna plug, scart and SVHS if you turn your power plug the “wrong” way. The only connection to the Powerline came from the condensators in the net filter. In EU the CE marking tell that the only wire that most be grounded should be marked yellow/green, and must not draw any current <10mA.
I’m sorry too tell you that in the whole EU no TV is connected galvanic to ground thru the 2 AC wires. That will mean that you could have 230Vac (110V ) on the chassis. That would mean that you would actually touch the Powerline on the antenna plug, scart and SVHS if you turn your power plug the “wrong” way. The only connection to the Powerline came from the condensators in the net filter. In EU the CE marking tell that the only wire that most be grounded should be marked yellow/green, and must not draw any current <10mA.
Thanks for clearing that up. I had been under the impression that Europe had adopted polarized plugs as North America has.
ground loop
Try this first for video:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=180-075
For audio loops:
http://www.edcorusa.com/sound/matchers/s2s10k_10k.htm
If you have one of each you will always be able to get the show on the road when visiting friends.
Try this first for video:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=180-075
For audio loops:
http://www.edcorusa.com/sound/matchers/s2s10k_10k.htm
If you have one of each you will always be able to get the show on the road when visiting friends.
It's true, when I get off the calbe antenna of the TV, the noise gone.
So, thank you very much for the help, I will do or buy a filter..
Thank you !!!
So, thank you very much for the help, I will do or buy a filter..
Thank you !!!
You are mistaken about north american wiring. On two pin plugs, one is the "hot" and the other is the "neutral". Neither is ground. Only 3 pin plugs have a ground, and as dalbjerg said, it must never carry a significant current.
I must correct you a little here or make it clearer. Older TV has "hot" chassis via a fullwave rectifier bridge.dalbjerg said:
IF the TV has some sort of audio output, like headphones or speaker, the TV has:
1 An output transformer, older TV's
2 Cool chassis (not hot)
No TV has "hot" audio output, not very safe
macboy said:
No, I'm not. What makes the neutral "neutral" is that it is attached to ground in the circuit panel, hence it can be part of a ground loop.
leadbelly said:
Some parts do have somewhat polarized plugs like France who has a plug (Schuko style) which can only be inserted one way, GB with their dinosaur (in the most positive sense) plug or Switzerland which have fully polarized plugs.
The TV is new.
What I want to say, it is that the TV is not grounded.
The "negative" of the RCA plug is connect with the "negative" of the coaxial plug of the "wall" because they are together inside the TV.....
The noise came from the antenna cable.
What I want to say, it is that the TV is not grounded.
The "negative" of the RCA plug is connect with the "negative" of the coaxial plug of the "wall" because they are together inside the TV.....
The noise came from the antenna cable.
Unplug the antenna and measure the ground of the antenna. Maybe someone has defect TV connected. I had this problem where I lived before. The ground of the antenna was at 230 V potential. When I connected my stereo to the headphone jack. Guess what happened?arold19 said:
The TDA2002 exploded! and the feedback resistors went to heaven
I'm afraid that you are.
The neutral is connected to ground at some point (nowhere near your breaker panel or your house!). However, no electrical device should ever consider the neutral to be ground, and it along with the hot wire must be isolated from the case or anything else that a person may come into contact with. Currents flowing through the Neutral wire will create a potential difference (voltage) between it and ground. This isolation (usually galvanic isolation, i.e. transformer) also completely eliminates the possibility of a ground loop via the neutral wire.
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