Ground loop question

Started by ericar123, June 21, 2017, 01:00:59 PM

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ericar123

Hi
I know there are a lot of you in this group that are a lot smarter than me so I have a question I would like help with. My music setup is based around a PC that is grounded and has many pieces of music gear plugged into it through USB , Midi and analog audio. I use an M-Audio 1010LT PCI sound card. I also use powered Event monitor speakers plugged into the sound card. With all of this music gear being plugged into different outlets, I have some ground loop issues. If I cut the ground on everything except the computer, would everything connected to it still be grounded? I would expect this would stop my noise. I am pretty sure that audio cords and USB cords have a ground wire but am not sure about midi. Any thoughts would be appreciated. By the way, I did try a brand new Steinberg usb audio interface and still had the same noise. It does disappear on both the sound card or usb interface when I unplug all of the USB gear.

Elantric

Best to review both these threads


Fix your Audio Ground Loop Buzzes and Noises
https://www.vguitarforums.com/smf/index.php?topic=2078.0


USB Noise - audio output has enormous noise with USB cable connected
https://www.vguitarforums.com/smf/index.php?topic=367.0

gumtown

I would not advise cutting the ground connections on mains powered devices.

Start by grouping all your mains plugs together as close as possible, using one large multi way power strip, keeping all the mains powered earth connections from one common 'star' point.

You also have analog and digital devices sharing the same earth connection through your USB cable, and the close proximity of computers and monitors to audio equipment. All these can induce unwanted noise.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

ericar123

Thanks for the replies. Last night I decided to rip apart my setup and start to eliminate noises one at a time. I have always had a problem with noise from my graphics card that you can hear  with every mouse movement or webpage or app movement. I have had the same problem with 2 different m-audio pci cards and 2 different computers with 2 different graphics cards. I unplugged everything from my computer except wireless mouse and keyboard and powered
monitor speakers . I then tried plugging in the monitor speakers in using an extension cord without ground and then plugging in the computer without ground. Neither stopped the noise. I can just click my mouse on the desktop and drag it and I will hear static type noise. When I tried the Steinberg usb interface the noise was the same. I have even tried different refresh rates on the graphics card as well as different settings on my audio card with no luck.

Elantric

#4
If you get static noise from your mouse movement it's because your video card shares IRQ with another device  or is hogging the PCI bus to the CPU

it's a typical windows computer problem it impacts probably 60% of them






type  "msinfo32" in the Start menu and you can review IRQ conflicts

( first thing I do when looking at a potential computer at Best Buy )

Many high-end gaming graphics cards will also starve the CPU Clock cycles with resulting exhibited  "static noise when the mouse moves" behavior


http://lmgtfy.com/?q=static+noise+when+the+mouse+moves%22+behavior

Some claim using a powered USB hub to connect your USB mouse to the PC may solve the static noise issue

http://www.tomshardware.com/forum/324159-28-hear-mouse-moving-windows-speakers

ericar123

Once again, Thanks for the reply. This gives me more stuff to try.