Noise when using Digital Coaxial on Pioneer VSX-D711.

[cvitanic]

Hi guys... I`ve tried everything I can think of and still can`t figure this out.

I´ve been using this receiver connected to a Soundblaster Live soundcard in my PC without any problems. I use an analog mini plug to stereo RCA connectors in the AUX input.

Now, I purchased a DVD Player with HDMI connection, which I plugged to a 26 inch LCD. The idea is to connect the digital output on the DVD player (it only has coaxial) to the digital input on the receiver.

I did so and got the audio to work with no issues. It`s when I switch back to the sound card (AUX Input) that I get noise, audible when I set the volume over -30 dB. The Pioneer support page says that it might be "digital noise" and to be careful about not having the cable looped over electronic components, which is not my case.

Anyways, the noise stays even if I turn off and unplug the DVD player. It only stops if I disconnect the coaxial cable from the unit. I tried switching to other inputs on the receiver with no luck.

Any help will be appreciated ! Thanks a lot !!!

 

[majorloser]

It almost sound like it could be a ground loop problem. Is the noise a hum or buzz sound?

You could have a ground loop problem that is between the receiver (or computer) and the LCD display. The DVD player is just acting as the "pass through" for the current. By disconnecting either the coax or the HDMI cable from the DVD you could be just breaking the circuit. Just for S&G's try keeping the DVD player hooked up and unplugging the computer.

EDIT: Might even try changing the coax cable between the receiver and DVD player. Any good quality coax cable will do. Just in case it is some weird cable problem.

 

[cvitanic]

Well, we`re making some progress here !

First, I unplugged the PC with no results, so then I disconnected the HDMI from the LCD and... Voila ! No more noise ! BTW, to me it sounds more like a Buzz than a Hum.

Now, the question is: What should I do to fix this ???

Thanks again !

 

[majorloser]

Give me a few minutes to think about this........................

Are the LCD and the receiver plugged into the same outlet? If not, can they be?

 

[cvitanic]

They`re not, but I can try to...

PS: I did and still get the noise... What about some filters I`ve seen on other posts ? The issue is WHERE to put the filter, I`ve seen some for RF cables but I doubt there are any for HDMI, so maybe a filter to the AC plug of the LCD (Where I live we have 220 / 50 Hz. AC current BTW)

 

[Seth=L]

If you are getting no audio from the computer using the digital connection and you are getting noise it means the digital output is possibly off. I would go to your control panel and access your sound card (not Sounds and Audio devices) and shut off the analog output and turn on the digital output (coaxial). Be sure that you are using a mono RCA-1/8" adapter to connect the receiver to the digital SPDIF output, unless the audio card has an RCA SPDIF output then you can use any mono 75 ohm cable such as a composite (yellow) cable.

 

[cvitanic]

If you are getting no audio from the computer using the digital connection and you are getting noise it means the digital output is possibly off. I would go to your control panel and access your sound card (not Sounds and Audio devices) and shut off the analog output and turn on the digital output (coaxial). Be sure that you are using a mono RCA-1/8" adapter to connect the receiver to the digital SPDIF output, unless the audio card has an RCA SPDIF output then you can use any mono 75 ohm cable such as a composite (yellow) cable.

Well, I have the sound card through analog as I`m really not sure if this version of soundblaster sound card has digital out. Anyways, the ground loops is still there and I don`t think that switching to a digital out sound card will fix the problem.

I need to break the ground loop from the LCD to the rest of the appliances, which gets transfered through the HDMI cable to the DVD player and then to the receiver through the coaxial digital out. If someone has an idea how, please let me know.

Maybe it`s possible to use a filter on the RCA Coaxial from the DVD out to the receiver ? Do those filters even exist ?

 

[cvitanic]

Well, guess what. I came around the problem.

I just re-arranged the connections on the shoe and now I have all the appliances on the same wall outlet. I didn`t want to cram up a single outlet though, as I have two 19 inch CRT monitors, and when they power up they cause a sudden raise in amperage, so the automatic fuse on that part of the house circuit cuts the power.

That`s why I spread the connections on two outlets, but this is what is causing the ground loop.

 

[mtrycrafts]

Well, I have the sound card through analog as I`m really not sure if this version of soundblaster sound card has digital out. Anyways, the ground loops is still there and I don`t think that switching to a digital out sound card will fix the problem.

I need to break the ground loop from the LCD to the rest of the appliances, which gets transfered through the HDMI cable to the DVD player and then to the receiver through the coaxial digital out. If someone has an idea how, please let me know.

Maybe it`s possible to use a filter on the RCA Coaxial from the DVD out to the receiver ? Do those filters even exist ?

How does your cable TV come into the room and to your other components?
Someplace here is where that ground isolator needs to be placed but need to know what is coming in, what type of cables.

 

[majorloser]

Well, guess what. I came around the problem.

I just re-arranged the connections on the shoe and now I have all the appliances on the same wall outlet. I didn`t want to cram up a single outlet though, as I have two 19 inch CRT monitors, and when they power up they cause a sudden raise in amperage, so the automatic fuse on that part of the house circuit cuts the power.

That`s why I spread the connections on two outlets, but this is what is causing the ground loop.

If nothing else, can you place all the items that use audio cables (digital, analog and HDMI) on the same circuit?

At least get the receiver and the LCD on the same circuit. It appears the ground loop was traveling through the DVD player from the receiver and LCD display.

 

[cvitanic]

Well, I replaced the shoe and got the noise back. Following the directions of some forum members I noticed that unplugging the coaxial cable (cable TV) from the LCD stops the noise, so I guess it`s a problem with the ground of the cable TV.


PS: I called my cable company and the engineer said that this was a common problem with digital appliances, and that a solution might be connecting a separate grounding copper rod to any metal part of the appliances. Would this work ? Sort of creating a dedicated ground for the system.

 

[mtrycrafts]

Well, I replaced the shoe and got the noise back. Following the directions of some forum members I noticed that unplugging the coaxial cable (cable TV) from the LCD stops the noise, so I guess it`s a problem with the ground of the cable TV.


PS: I called my cable company and the engineer said that this was a common problem with digital appliances, and that a solution might be connecting a separate grounding copper rod to any metal part of the appliances. Would this work ? Sort of creating a dedicated ground for the system.

Well, there was a reason for my question, really
And, you answered where the trouble is coming from as that is the vast majority of the cases, the cable TV.

Here is your fix as this has also helped the vast majority of the people:

http://www.cencom94.com/gpage.html8.html

The isolator is the top part. Place it near the entry point and try it. Don't place it closer to the TV or some other component as there may be another path for this ground loop that you don't see at first.

You may want to copy that page and if you have a Radio Shack near you, they may carry something similar and don't have to pay shipping and you gain some time.

 

[cvitanic]

Well, I`ll use the specs and try to get me one as I`m in Chile, not sure if the store you recommend ships internationally, but anyways due to shipping costs it`ll be more convenient to find it here.

Just to be sure, the product is the isolator on top of the page ?