Loud interference in my system!

[blinkthis69]

Hi guys, new member here. I really need some help setting up my yamaha AV receiver. Earlier this year I upgraded from a small set of computer speakers . I have my laptop connected via usb to an external soundcard (Roland EDIROL ua4-fx) and its output is connected to my HTR-6030 reciever. I also have my xbox 360 sound through a set of inputs (although the component cables go to the tv, not through the reciever).
Currently that is all thats connected. The xbox channel is clear and produces a very strong stable signal at high volumes but the computer output (which i play all my music and most videos through) has a horrible backround feedback-like sound. I've done a lot of things to try fix this (like trying different inputs / outputs and different cables) but these quickfixes did not solve the problem. If anyone can get back to me with some help it would be GREATLY appreciated its getting to the point where if i cant fix it i might upgrade the system which no student wants to have to do.
Im using the stock 5.1 speaker kit that came with it.

 

[sparky77]

Try running the laptop off battery power, if the noise goes away, it's a ground loop. If that's the case, and you have a grounded plug on the power adapter, try using a cheater plug to eliminate the ground.

 

[blinkthis69]

Oh man. I think the time it took between me finishing your post and yanking out my dell's power cord was half a second - AND IT'S FIXED! Thanks so much dude. I got about 3 hours of battery power so I've put some music on and am making the most of it.

What is this cheater plug i will need after that though? Cheap?

 

[Exit]

What I think what a “cheater plug” refers to is a ground plug adapter where you plug in a 3-prong cord connector into one side and the plug makes a 2-prong connection into the wall socket. The adapters I have seen also have a green ground wire which you hook onto the receptacle plate screw. If you have a ground problem, then I believe you “cheat” by not connecting the ground wire. These adapters are sold in the electrical section of Home Depot or Lowes and they are only a buck or two. Some people just cut off the power plug ground but that is not advisable if you ever want to sell that piece of gear because a lot of people want the equipment in original condition. If this is not what blinkthis69 is referring to he or someone else will need to clarify,

 

[Cheetah]

Haven't used one of these in forever, but I think this is what he's referring to:

I would think that would correct the ground loop.

Also, make sure to set the sound level in your sound mixer to 75% or less, any higher can cause clipping and distort sound, or at least that's what I was told...

 

[mtrycrafts]

Hi guys, new member here. I really need some help setting up my yamaha AV receiver. Earlier this year I upgraded from a small set of computer speakers . I have my laptop connected via usb to an external soundcard (Roland EDIROL ua4-fx) and its output is connected to my HTR-6030 reciever. I also have my xbox 360 sound through a set of inputs (although the component cables go to the tv, not through the reciever).
Currently that is all thats connected. The xbox channel is clear and produces a very strong stable signal at high volumes but the computer output (which i play all my music and most videos through) has a horrible backround feedback-like sound. I've done a lot of things to try fix this (like trying different inputs / outputs and different cables) but these quickfixes did not solve the problem. If anyone can get back to me with some help it would be GREATLY appreciated its getting to the point where if i cant fix it i might upgrade the system which no student wants to have to do.
Im using the stock 5.1 speaker kit that came with it.

Before you buy and use one of those cheater plugs, defeats the purpose of a ground connection, I see your system is also connected to the TV.
Do another experiment first:
disconnect any and all connections to the tv from the audio gear and use the 3 prong power cord and see if that sound is still there. The TV can cause that ground loop as well, but there is a safer solution for that, a ground isolator for the video connections.

 

[sparky77]

Does your powersupply infact have a three pronged power cord? Some computers even with two pronged cords have been known to cause ground loop issues, even though theoretically they should be isolated by the transformer in the power supply, and this is particularly common in the Dell laptops. The computers tend to use a common ground through out the entire system to prevent radiated noise that could interfere with other equipment in close proximity, with no regard to connecting the laptop to a surround system. If you don't have a three pronged plug you'll need a 120v isolation transformer to eliminate the problem or simply run off of battery power.

 

[zumbo]

Before you buy and use one of those cheater plugs, defeats the purpose of a ground connection, I see your system is also connected to the TV.
Do another experiment first:
disconnect any and all connections to the tv from the audio gear and use the 3 prong power cord and see if that sound is still there. The TV can cause that ground loop as well, but there is a safer solution for that, a ground isolator for the video connections.

Calrad RF Isolation Transformer. $12

Description, and ordering information toward the bottom of this page: http://www.bluejeanscable.com/store/rf/index.htm