IPB

Welcome Guest ( Log In | Register )

> Upload forum rules

- No over 30 sec clips of copyrighted music. Cite properly and never more than necessary for the discussion.


- No copyrighted software without permission.


- Click here for complete Hydrogenaudio Terms of Service

Irritating noise coming through speakers
liamoforange
post Jul 29 2012, 20:18
Post #1





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



Hi,

I am getting this annoying noise through my speakers. It's like there are crickets in my computer trying to send me subliminal messages in morse code.

A sample is attached.

1. It appears once the PC powers up.
2. It appears irregardless of what sound card is used either onboard sound, or external sound card
3. It appears irregardless of what slot external sound card is installed in
4. All cables are shielded.
5. I am running a cable to an external pre-amp and then to my amp.
6. When cable from PC is disconnected the pre-amp is dead silent, when attached the noise interferes with all functions. i.e. phono
7. When PC is off, no line noise on any channel in pre-amp.
8. Sound appears when using a different source, i.e. a receiver instead of pre and power amp.
9. Have swapped out multiple cables, even had a custom shielded cable made to run from PC to pre.
10. All drivers are installed properly and up to date.

Asus P5Q-deluxe
X-Fi Platinum sound card
Win 7 x64
4gb ram

Any and all help to troubleshoot and eliminate this problem will be greatly appreciated.
Attached File(s)
Attached File  Memo1.m4a ( 99.42K ) Number of downloads: 456
 
Go to the top of the page
+Quote Post
 
Start new topic
Replies (1 - 15)
JJZolx
post Jul 29 2012, 20:59
Post #2





Group: Members
Posts: 396
Joined: 26-November 04
Member No.: 18345



Can you provide any more details about the PC? CPU, hard drives, other cards, peripherals, case, fans, neon lighting, etc.

Have you tried plugging any other sources into the preamp/amp combo? An iPod or CD player or something.

This post has been edited by JJZolx: Jul 29 2012, 20:59
Go to the top of the page
+Quote Post
Nick.C
post Jul 29 2012, 21:02
Post #3


lossyWAV Developer


Group: Developer
Posts: 1791
Joined: 11-April 07
From: Wherever here is
Member No.: 42400



Where is your router? When I had my router on the same desk as my 4.1 speakers, I got terrible interference from the router.


--------------------
lossyWAV -q X -a 4 --feedback 4| FLAC -8 ~= 320kbps
Go to the top of the page
+Quote Post
Fandango
post Jul 29 2012, 22:23
Post #4





Group: Members
Posts: 1548
Joined: 13-August 03
Member No.: 8353



That's a sympton of your typical ground loop. IBM compatible PCs were never intended to be audio equipment initially, that's why their electrical ground is connected to the audio jack's shield (screening), in fact it's like this: ground is connected to any shield of any connector, the audio jacks happen to be among them, sadly they usually don't get a special treatment by sound card or mainboard manufacturers. When there are more than two cables connected from your PC to your amp it basically creates an antenna that could pick up anything and when those radio singals are in the audible frequency range, well then they're audible. It can also happen when you have other problematic equipemt attached to your amp in addition to your PC.

The shielding of the cables is not the solution to your problem, it is the problem. But getting rid of any extra shielding won't work either, line audio connector's signalling is single ended, their shield is essential for the actual audio transmission, break that and you have no audio. Looking at the X-Fi Platinum the card's back panel which is conencted to the chassis which is connected to ground is also functioning as the screening. You can't fix it by simply cutting the loop.

You could try a radically different arrangement of your equipment, basically move the antenna away from the noise inducing source, unfortunately from the sound of the sample you've provided it's obvious the source is your PC itself.

Or you could use two DI units for each analog audio connection, creating galvanic isolation of the ground/shield antenna, breaking the loop that way. If you know how to use a soldering iron it's probably much cheaper and more elegant (no redundant functionality and parts of the DI units) to create such a device yourself. Those devices complete with four RCA jacks might even be available for sale somewhere, something such as this.

Another solution would be to use a digital audio connection between your PC and your amp instead (probably need a different pre-amp for that).

For a quick but probably inconvenient fix, that migh not even work in your case: try to disconnect your turntable from the pre-amp, not a proper solution but that worked for me once, or basically terminate all except one audio connection from your PC to your pre-amp.

This is such a common problem in sound engineering, people here probably have some more tips and tricks for you.

This post has been edited by Fandango: Jul 29 2012, 23:03
Go to the top of the page
+Quote Post
Glenn Gundlach
post Jul 30 2012, 04:16
Post #5





Group: Members
Posts: 369
Joined: 19-April 08
From: LA
Member No.: 52914



You have a ground loop from hell. It's the kind of noise I've heard when the shield is not connected between units and the ground is coming from the power cords. If it were mine I'd begin by disconnecting as much as possible including the monitor. How many units use 3 wire cords? I can't tell you to run without grounds as a safety issue but temporarily lifting the ground for test purposes is OK. Are any of your shielded cable home made? Are the shields connected at both ends? Any units plugged onto a different power circuit?

G
Go to the top of the page
+Quote Post
liamoforange
post Jul 30 2012, 06:12
Post #6





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



Thanks everyone, it is appreciated. I am going to try pulling the system apart and see what I can come up with for a solution, following some of the suggestions here.

A few additional details. This got markedly worse with the addition of a new modem to the system. It was there with the old modem, but about 5% of what is there now. That modem was failing and would not keep connected and needed replaced and the model is no longer available.

The "noise" (crosstalk?) gets worse the more data is coming down the line. If I am doing nothing online, it is minimal, surf it gets worse, stream live tv and it is pretty damn awful.

The entire audio chain is powered from dedicated sockets that have their own dedicated line from the fuse box.

The entire PC chain is powered from a Belkin UPS plugged into a different line from the box.

The only connection between the two parts of the system is the line out from the sound card to the pre-amp.

I have disconnected every cord in and out of the back of the PC save for the line out to the pre-amp, the power cord, and the line in from the modem. Makes 0 difference.

I did move the modem to another part of the room, about 25' away but it made no difference.

I have plugged other pieces, ipod and cd player, into the pre-amp and the noise is there with all of them if the line from the PC is connected, even if other line out selections are made. Disconnect the PC cable it goes away.

Keep firing suggestions for when I can take the day and rip this apart.

One other thing, I have bought an E-mu 1616M PCI-e with a separate break out box. I really don't want to eat the cost of it by opening it if this problem cannot be resolved. Would the grounding in that sound card/breakout box eliminate this situation?

Finally, could it be a failing part in my PC that is causing this?

Thank you. smile.gif

This post has been edited by liamoforange: Jul 30 2012, 06:15
Go to the top of the page
+Quote Post
liamoforange
post Jul 30 2012, 07:52
Post #7





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



Fandango, I removed the phono cable from the pre-amp so the only cable going into it was from the PC and it made no difference.
Go to the top of the page
+Quote Post
[JAZ]
post Jul 30 2012, 08:57
Post #8





Group: Members
Posts: 1783
Joined: 24-June 02
From: Catalunya(Spain)
Member No.: 2383



I am unsure if this applies to you, but my solution on this case was a very simple one (In my case, all the equipment was connected to the same socket, which did not have a ground cable. You say you have two independent lines).

Basically, i connected a cable from the PC to the ground of the integrated amp. (I.e. from one screw of the back of the desktop tower to the ground screw in the integrated amp). I believe you might already have one from the phono turntable to it, since for phono it is even more important.

This reduced the ground loop a lot in my case.

This post has been edited by [JAZ]: Jul 30 2012, 08:58
Go to the top of the page
+Quote Post
liamoforange
post Jul 30 2012, 22:07
Post #9





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



Fandango, I was able to locate that part you linked to locally for $18. I installed it, and it was a success!!!!! smile.gif biggrin.gif beer.gif

Thanks so much everyone, the noise is now gone from the system.

I have a question, does this part at all degrade SQ? Like I said the goal is to install an E-mu 1616m to record a friends music for him, and don't want to be introducing something into the chain that will take away from their studio work.

Again, thank you everyone! I was going a little crazy there and am starting to feel sane again. smile.gif
Go to the top of the page
+Quote Post
mzil
post Jul 30 2012, 23:03
Post #10





Group: Members
Posts: 605
Joined: 5-August 07
Member No.: 45913



QUOTE (liamoforange @ Jul 30 2012, 01:12) *
...The entire audio chain is powered from dedicated sockets that have their own dedicated line from the fuse box.

The entire PC chain is powered from a Belkin UPS plugged into a different line from the box. ...

...

I have disconnected every cord in and out of the back of the PC save for the line out to the pre-amp, the power cord, and the line in from the modem. Makes 0 difference.
[emphasis in blodface by me]

Ground loops are caused when there are two or more "ground potentials" connected to the same device and not limited to AC ground wires but rather ALL wires. Adding transformers to isolate the problem works, but it is a band-aid approach and may degrade the sound (notice that advertised one makes no claims as to a flat response below 40 Hz). The better approach, if at all possible, is to reconfigure the system so all your devices receive their ground from the same EXACT source (called a "star grounding" topology) like one large power strip plugged to a singular AC outlet (UPS allowed, as long as it doesn't also connect to telephone/internet/cable etc. too), and then apply any isolation transformer devices, only if still needed, to things like the wire that feeds the modem the internet.

I have placed in boldface the probable problems with your setup. You mention using different outlets and by leaving the modem attached you have a new, alternate ground source (potential), the wire for the, I assume, cable company wire.

Disconnect that cable wire, in addition to using a star grounding design, and if that's indeed the problem wire, the correct transformer to buy for it is this .

EDIT TO ADD: Yikes, that price is ridiculous! I buy them for $10 to $20 USD usually. I'm hunting for a better source and will report back, but I'l leave the link as is, for a picture reference only, for now.

This post has been edited by mzil: Jul 30 2012, 23:21
Go to the top of the page
+Quote Post
mzil
post Jul 30 2012, 23:13
Post #11





Group: Members
Posts: 605
Joined: 5-August 07
Member No.: 45913



OK, here's a more reasonable price with free shipping.

Many places that sell it don't even mention the ground breaking aspect and simply refer to it as a "surge protector" but if you read the outer casing you'll see it is.
Go to the top of the page
+Quote Post
liamoforange
post Jul 30 2012, 23:42
Post #12





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



QUOTE (mzil @ Jul 30 2012, 17:13) *
OK, here's a more reasonable price with free shipping.

Many places that sell it don't even mention the ground breaking aspect and simply refer to it as a "surge protector" but if you read the outer casing you'll see it is.


Hi, thanks but I think there was some confusion there. I am using a DSL modem, not a cable modem. I don't think that part will work with my current configuration.

I will try getting everything on the one circuit and see if I can eliminate the noise that way. Short term I have a solution that will keep me sane, but considering I installed dedicated lines for my audio gear in the room I will need to find as organic a solution as possible.

smile.gif
Go to the top of the page
+Quote Post
mzil
post Jul 31 2012, 00:13
Post #13





Group: Members
Posts: 605
Joined: 5-August 07
Member No.: 45913



Oh, OK, I don't know off the top of my head the correct device to break the ground connection from a DSL line, however if you simply disconnect it from the back of the PC, as a diagnostic test, as well as use star grounding [or what the attached link calls "single point" (like the rays of a star leading to its core)] I'm confident you wont have to use that RCA in line device and hence not worry about any possible compromise in sound performance it may invoke.

Eliminating Hum and Ground Loops

This post has been edited by mzil: Jul 31 2012, 00:17
Go to the top of the page
+Quote Post
mzil
post Jul 31 2012, 00:31
Post #14





Group: Members
Posts: 605
Joined: 5-August 07
Member No.: 45913



Wait, I just realized. You may still need that device I linked to, if you have cable TV or sat TV connected to that same audio system, even if the peripheral device isn't turned on. The offending ground loop can come from ANY device and ANY connected wire, be it AC, USB, RF, RJ45, Ethernet, cable, sat., 12V triggers, sub out, video outs, etc.

It seems weird since you have no problem until you connect the PC, so it''s hard to believe it has anything to do with some unused device that gives no problems when you use IT, but trust me, it may matter.

This post has been edited by mzil: Jul 31 2012, 00:37
Go to the top of the page
+Quote Post
liamoforange
post Jul 31 2012, 00:34
Post #15





Group: Members
Posts: 24
Joined: 26-October 06
Member No.: 36794



QUOTE (mzil @ Jul 30 2012, 18:31) *
Wait, I just realized. You may still need that device I linked to, if you have cable TV or sat TV connected to that same audio system, even if the device isn't turned on. The offending ground loop can come from ANY device and ANY connected wire, be it AC, USB, RF, RJ45, ethernet, cable, sat., etc.


We don't have cable or satellite TV, no TV at all actually, just a computer monitor. The only line coming in is the phone line, with the DSL.

I will still try and create a situation that eliminates the ground noise without the filter, and use the control test you suggested.
Go to the top of the page
+Quote Post
Glenn Gundlach
post Jul 31 2012, 03:19
Post #16





Group: Members
Posts: 369
Joined: 19-April 08
From: LA
Member No.: 52914



QUOTE (liamoforange @ Jul 30 2012, 13:07) *
Fandango, I was able to locate that part you linked to locally for $18. I installed it, and it was a success!!!!! smile.gif biggrin.gif beer.gif

Thanks so much everyone, the noise is now gone from the system.

I have a question, does this part at all degrade SQ? Like I said the goal is to install an E-mu 1616m to record a friends music for him, and don't want to be introducing something into the chain that will take away from their studio work.

Again, thank you everyone! I was going a little crazy there and am starting to feel sane again. smile.gif


They claim response 40 Hz to 32 KHz. I believe it's just a pair of transformers to 'galvanically isolate' the grounds which eliminates the currents. I listen to music with sub 30Hz response so I would look for another solution - and there is one but it'll cost you more than 5 bucks. If you're happy with it as it is, just use it and enjoy. The 'high end' solution is to use differential amplifiers that will subtract out the ground noise and leave you with DC to potentially hundreds of KHertz response. I know this works because I used this 'trick' in my car 20 years ago.

I'm glad you have it working.

G
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 18th September 2014 - 10:16