Problem with Crackling/morse code in speakers

[morefiend]

I have the Fatal1ty 990FX Pro motherboard and use a Cyborg R.A.T.7 mouse and Eclipse Keyboard. Recently I picked up CM Storm's Sirus True 5.1 headset. I installed them using the two usb connectors and have a low crackling, morse code sound when there is no sound....just staring at the screen, I can hear it and it gets slightly louder when I move the mouse. I've tried moving the connectors for the headset to different mouse ports and have moved the the RAT 7 from teh dedicated mouse port to other usb 2 or 3 ports and still have the noise. I contacted CM Storm who suggested that it was a USB grounding issue with the motherboard. How would I go about fixing a grounding issue? My case is a Cougar AF-2 Solution...I have aboslutely zero issues with this setup other than the crackling, morse code noise..

Thanks,

[parsec]

Re: Problem with Crackling/morse code in speakers

The noise you described is the typical electrical interference noise that can happen with PC audio. Some (most) boards I've used have it, others don't.

Your description of the noise is perfect, including the "morse code" sound, which just seems so weird to me. The inside of a PC is really an audio signal's environmental hell, with all the very high frequency digital switching going on. The extra noise heard when you move the mouse is just what I get too, since the signal from the mouse to board and back is changing or increased, so more or different noise. I would not blame your gaming mouse for the noise, since I hear the same thing using a plain, cheap (compared to your mouse), USB mouse.

To fix it will take work and luck, and may never work at all, in my experience.

If you use the USB connections on your PC case, try the ones on the rear I/O panel.

If you connect your mouse to the USB connections on the rear I/O panel, the next suggestion will not help. If you connect your mouse to the cases USB connectors, check the routing of the internal USB cable that connects to the board. Try to keep it away from the power supply and its cables. Actually, try to keep it as far away from any hardware in the PC as possible, so it won't pick up noise. Most case manufactures don't use shielded cable for the USB connections, so they have no noise protection. Make sure the connector is firmly in place in the board.

Grounding is trial and error. First, are you sure your AC wall socket is properly grounded? You use the three prong AC cable to the PS, right? Actually, my AC ground was fine, cable too, and made no difference, but worth checking.

When you built that PC, do you recall if it looked like there were bare metal or solder like spots around the holes where you put screws through the mother board to the standoffs in the case? Most boards are like that. If yours does, get a piece of single conductor wire about one to two feet long, insulated, but does not need to be thick, thin wire is fine.

CAUTION! CAUTION! Proceed at your own risk!!! UNPLUG THE AC POWER TO THE PC FROM THE WALL SOCKET!!!!! This is also not guaranteed to work

Some cases come with black painted screws, that insulate them. I've wondered why the screw holes in mother boards have those bare metal contacts around them. Could it be to provide a ground connection from the board to the PC case, through the standoffs? I've never seen that discussed anywhere, but it would not surprise me. If you have black screws, try some bare metal ones before doing anything else. If that doesn't work, continue below.

With the PC off and unplugged, unscrew one of the mother board screws at the bottom of the board, and close as possible to the USB plugs for the case. Strip less than 1/2 inch of insulator off the wire, and make a little loop in the wire to fit around the mother board screw, and have the bare wire contact the bare contacts around the mother board screw holes, and tighten the screw.

Next you want to connect the other end of that wire to the PC case. Since most cases are painted, you need to find or make a small bare metal spot to make an electrical connection. Any hole inside the case that you can put a screw in, or has one in it now will be fine, just be sure it makes electrical contact. Even better would be a screw on the power supply case, since that is grounded right to the third wire of the AC power cable. You may need to experiment with different connections points on the mother board and case before this does any good.

You can also check the USB connections on the PC case, by taking apart the area where the USB and other headers are mounted. There should be a ground wire there somewhere, unless it is mixed in with all the other wires. If you have no knowledge of electronics, don't just try random connections or jumper wires, things WILL get damaged if you do.

Good luck with this. If you never solve it, you can do what I do, use the SPDIF digital output from the PC into a receiver or headphone amplifier. The digital signal will not send any noise along with it. OTOH, that will only be stereo, unless you have a special Dolby or DTS surround sound card.