Loud distortion with USB device

[theoilweapon]

I had been using my VTF-2 quit enjoyably until I hooked up my Yamaha RP-U100 with a USB cable. It sounds lovely from an analog source with low level inputs or speaker level. But when the usb is selected as a source, there is a high pitched squeal with some crackling and booming (you can hear it from your chair at even the lowest volume).

Here is the background on the receiver: http://www.yamahamultimedia.com/yec/products/cavit/rpu100.asp

Its subwoofer output "...is the sum of the channels..." and cannot be controlled from the receiver whatsoever. You cannot change the gain or crossover of the output.

Using speaker level inputs there is no noise using USB. So I think, distortion from my computer? I unhook the usb cable from my usb hub and put it directly into the computer (Dell Inspiron 8200). No change. HERE IS THE WEIRD PART:

I can actually hear changes in the distortion when i put a load on my hard drive (like opening internet explorer).

Conclusion: There is a problem with the subwoofer output on my receiver when USB is the source. This problem is directly connected to my USB jacks, where interference is somehow introduced.

Questions: Is there any way to filter this?

I apologize for the clutter, I am quite upset. Please ask any questions that might help you understand this problem. Thank you very much for your help!

[Michael Bain]

Your best bet would be to call Hsu tommorow. Also try to get in contact with Yamaha tech support.

[theoilweapon]

Originally posted by Michael Bain
Your best bet would be to call Hsu tommorow. Also try to get in contact with Yamaha tech support.

I spoke with people at both companies. The Yamaha guy suggested troubleshooting by using speaker-level outputs. I told him I would try that, then talk to the HSU, then call him back. Someone at HSU ruled out radio interference after I explained my situation to him... I think the data points right to the USB connection and the subwoofer output but I don't know how or why. :confused:

Ahhh the search for convenience is ironically inconvenient

[Sasha_G]

I've had a similar issue with USB devices. I found that ground loops noise can travel on usb cables. Even hard drive sounds then get picked up.

Making sure that:
1) the ground plug, or third prong, is not used on any of the equipment
2) if cable tv or satellite tv is plugged into the system, it can also cause this. A RadioShack ground loop isolator can fix the issue.

In my case, my laptop always had awful noises when plugged into the receiver. I tried getting an external soundcard to fix the problem, but it didn't work. I then used a cheater plug on the computer to "float the ground plug", and all the computer noise was gone!

[theoilweapon]

Originally posted by Sasha_G
I've had a similar issue with USB devices. I found that ground loops noise can travel on usb cables. Even hard drive sounds then get picked up.

Making sure that:
1) the ground plug, or third prong, is not used on any of the equipment
2) if cable tv or satellite tv is plugged into the system, it can also cause this. A RadioShack ground loop isolator can fix the issue.

In my case, my laptop always had awful noises when plugged into the receiver. I tried getting an external soundcard to fix the problem, but it didn't work. I then used a cheater plug on the computer to "float the ground plug", and all the computer noise was gone!

:D :D :D

First I tried putting the cheater plug on the power cable to my laptop. There wasn't any change but I did notice a change in the sound of the distortion when I unpluged the power cable(switching to battery power). Then, just for fun I put the cheater plug on the subwoofer power cable. Distortion gone!!! I was really sad that I would have to scrap the whole receiver and I would have if you didn't help! Thanks for going out of your way. I'll go grab another cheater plug for my computer...

:D :D :D

Thanks again, you have no idea how glad I am to have this fixed!

[Sasha_G]

Wonderful!