Background noise

**Trench** · 04-19-2008, 08:48 PM

Hello,

I finally worked out my ground loop issue. I did this by grounding straight to the body and wiring straight into the factory amp, removing the HU completely). But now I still have one remaining issue.

I can hear some strange background noise through the speakers, almost inaudible expect when I turn the amplifier up (actually an after market CD deck with aux in). It has no effect if I Mute the sound card, so it would seem it is internal interference.

This noise is nothing new to me, as for many years I have always experience this same sound issue on my desktop computers when there is no sound playing the the speakers are turned up all the way

It is a strange noise to explain, almost like a rapid lowpitch drum roll that comes and goes when accessing files (hd spinning up, but not a whine) but , going by what I've noticed in the past, is also cause by moving the mouse.

I would simply throw this up to the cheap internal sound card, but I am using an external DAC and still get this issue.

any thoughts?

Thanks,
Dustin

**pancit175** · 04-19-2008, 09:31 PM

This type of sound is very typical. Not really much you can do about it because it is on the motherboard or picked up through the usb. I was able to eliminate any such noise when I upgraded to spdif optical.

**Trench** · 04-26-2008, 03:08 PM

That is what I was afraid of.

Does your motherboard have onboard Optical out, or did you have to by an adapter/card

**pancit175** · 04-27-2008, 07:41 PM

I bought the inexpensive (which means I forgot how much but its not too much) turtle beach roady micro, I think thats what its called. Its just a usb dongle and comes with the optical cable 3.5mm adapter. I just got it for the limited software support for the hardware. Or if your MB has onboard spdif you can get one of those digital coax-to-optical converters that requires 5V for approx $30-50. I saw some where online instructions on how to build your own one of those. If you do decide to go that route, make sure you get the coax input to optical output, and not the other way around.

**pancit175** · 04-27-2008, 07:44 PM

The only way I can think of to try to eliminate this sort of noise is to install ferrite chokes at each end of the cables going into the device making this noise. Including any power wires.

**ajscomp372** · 04-29-2008, 12:30 AM

I have heard from some people that grounding directly to the battery is better than grounding to the body. I'm really not sure which is the best, but you could try both and see which one works better.

**Trench** · 04-29-2008, 11:25 PM

Originally Posted by pancit175

The only way I can think of to try to eliminate this sort of noise is to install ferrite chokes at each end of the cables going into the device making this noise. Including any power wires.

hmmm. Something I never would have though of ; I may have to give it a try.

After I fix my returning Ground loop...

Yeah, Happy times

Bah

Originally Posted by ajscomp372

I have heard from some people that grounding directly to the battery is better than grounding to the body. I'm really not sure which is the best, but you could try both and see which one works better.

From what it seems, most seem to agree that grounding straight the the body with the shortest run possible is the best route, but just like most any other issue out there, I have heard stories supporting either method.

**ArcaneDreams** · 05-06-2008, 12:19 AM

Originally Posted by Trench

hmmm. Something I never would have though of ; I may have to give it a try.

After I fix my returning Ground loop...

Yeah, Happy times

Bah

From what it seems, most seem to agree that grounding straight the the body with the shortest run possible is the best route, but just like most any other issue out there, I have heard stories supporting either method.

Never ever ever run a ground wire longer than 12 inches. It will make your amp work much harder, it will heat up more, and you may even get worse noise.

**funkyphil** · 05-06-2008, 10:38 PM

I read all about what to do to get rid of this humming noise that keeps coming through my speakers. I even regrounded every ground, as well as reran all the power wires away from spearker wires.

If someone can lend a hand that would be awesome!

Thanks

Phil

**ArcaneDreams** · 05-06-2008, 10:55 PM

Post a diagram or something of how your wires are ran.

Perhaps purchase an external sound card just to see if it takes away the noise..if not, then return it.