MP3Car.com - View Single Post - Induced noise/Ground loop trouble shooting guide.

Nomader · 07-26-2006, 04:58 PM

hello.. good thread!!
I just installed everything.. and guess what. I am getting noise.. let me explain.
I have moved my head unit back in the trunk. by extending all the cables of the ISO connector all the way to the trunk. the HU works perfectly alone.. no problem there (by the way it is a veeery good Blaupunkt HU). Now I use the AUX in cable for blaupunkt which is not rca just a plain headphone jack that plugs directly into the soundcard..
I don't have noise when using headphones.
I don't have noise when using the HU alone.

so I guess the thing grounds through the Aux In cable right?
I had 2 noises.. one noise was constant.. it was there even when engine not running..(hard disk and mouse noises) the second was the whine which gets worse when i rev up..

iI used a good ground position..I tried to remove the ground cable from the ISO connector of the HU and ground the HU in the same ground with the PC...did not help a lot..
what i did and it actually removed the first noise was to place the HU on the metal case of my PC..that removed the hard disk nise by 95% and reduced the alternator whine by say 60%.. I stil heare that bird sing

any ideas how to remove it 100%??

I am using 4 AWG wires from the battery (for future expantions then 12 awg for the PC - just for 50 cm long) the ground is also 4 AWG and then it gets to 12 AWG (as the 4 AWG won't fit in the DSATX)

07-26-2006, 04:58 PM	#48
Nomader Maximum Bitrate Nomader's CarPC Specs Join Date: Apr 2006 Location: Greece Vehicle: Citroen Xsara 2002 Posts: 875 My Photos: ()	hello.. good thread!! I just installed everything.. and guess what. I am getting noise.. let me explain. I have moved my head unit back in the trunk. by extending all the cables of the ISO connector all the way to the trunk. the HU works perfectly alone.. no problem there (by the way it is a veeery good Blaupunkt HU). Now I use the AUX in cable for blaupunkt which is not rca just a plain headphone jack that plugs directly into the soundcard.. I don't have noise when using headphones. I don't have noise when using the HU alone. so I guess the thing grounds through the Aux In cable right? I had 2 noises.. one noise was constant.. it was there even when engine not running..(hard disk and mouse noises) the second was the whine which gets worse when i rev up.. iI used a good ground position..I tried to remove the ground cable from the ISO connector of the HU and ground the HU in the same ground with the PC...did not help a lot.. what i did and it actually removed the first noise was to place the HU on the metal case of my PC..that removed the hard disk nise by 95% and reduced the alternator whine by say 60%.. I stil heare that bird sing any ideas how to remove it 100%?? I am using 4 AWG wires from the battery (for future expantions then 12 awg for the PC - just for 50 cm long) the ground is also 4 AWG and then it gets to 12 AWG (as the 4 AWG won't fit in the DSATX)