Ground loop headache!!

[BigBoss]

Hey all,

I have a VE omega with a carputer setup i love it but... i am getting a ground loop hiss over my AUX in i am utilising the rear input in my head unit and still getting it. I am using a usb audio device and a quality cable connecting the two. any suggestions?

[sweefu]

Where are each of the things earthed? A lot of ground loop issues can be helped/solved by earthing them all to the same point, or if not to the same point then 'daisy chaining' all the earths together.

[BigBoss]

Well... the carputer is powered via a dc/dc converter in the boot connected directly to the battery (with a relay to switch power on/off). Then a usb cable runs to the head unit where a couple of things are connected most importantly the usb sound card. the card has a 3.5mm jack that runs to the rear aux of the head unit. i don't know where the head unit is grounded. Dose that help?

[BigBoss]

Would a simple ground loop isolator fix this problem? and if so could any one suggest a good brand?