Trench

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

MP3Car.com

 

pancit175

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.

__________________
"In the beginners mind there are many possibilities, but in the experts mind there are few."- Shunryu Suzuki
"Do it right or don't do it at all"

PROGRESS:
[-------90%-] (New Car=New Build)

Trench

That is what I was afraid of.

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

pancit175

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.

__________________
"In the beginners mind there are many possibilities, but in the experts mind there are few."- Shunryu Suzuki
"Do it right or don't do it at all"

PROGRESS:
[-------90%-] (New Car=New Build)

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.

__________________
"In the beginners mind there are many possibilities, but in the experts mind there are few."- Shunryu Suzuki
"Do it right or don't do it at all"

PROGRESS:
[-------90%-] (New Car=New Build)

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.

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.

ArcaneDreams

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.

MP3Car.com

 

funkyphil

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

__________________
www.philscustomcomputers.com

ArcaneDreams

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.

dopey273

Is this amp aftermarket or factory? If aftermarket, do you still have the noise when rca's removed from amplifier, try not to disconnect from source as the rca/signal in wire will act as an antenna and pic up noise. If not, then it's comming in from an outside source of the amplifier. Next take an extra pair of rca's and drape them over the seat or run out side and see if you sill have noise. What this does is eliminate any radiating noise in the car, ie ac, ecu, fuel pump,etc. If it's still there try running an additional temp ground to the same ground as the amplifier from your source ( sometimes when you get a difference in ground potential you get noise, ie difference of voltage due to ground paths of the vehicle.) Also if a quick easy wat to see if it's your source is to put an amplified speaker to the output of the soundcard , battery opperated, desktop speaker's, etc., basicly anything that doesnot share the same power supply as your source, which would be your cars electrical system. If you still get the noise then your source is bad. If not you have installation problems. Check and make sure that your gains are not maxed out , as these are not designed to be volume knobs. Sometimes if you crank up the gain tooo high it will induce noise. You can try turning them down and see if it reduces/diminishes. Noise is the hardest to troubleshoot as it can incorporate a ton of diff reasons... You could also try a inline rca noise filter...

Gdiddy31

Funny, i just started getting that same type noise in my car from the excelon deck, i can hear it with volume all the way down. Sort of a rumbly drum roll, that when looking at my subs does not look like clipping, and i hear my cd spin up or switching tracks it kind of bugs me.

pancit175

You'd be better off upgrading the grounding wire that goes from the chassis to the battery. Its part of the "BIG 3" upgrade

__________________
"In the beginners mind there are many possibilities, but in the experts mind there are few."- Shunryu Suzuki
"Do it right or don't do it at all"

PROGRESS:
[-------90%-] (New Car=New Build)

MP3Car.com