Hi guys,

Im using my iphone to play music through the AUX input of my stereo in my Skoda Octavia VRS Mk2. I have also got a belkin USB 12v adapter in order to charge the iphone at the same time.

Unfortunately when charging the phone i hear lots of noise and buzzing through the stereo, unplugging the USB and the audio is perfect.

The buzzing is made worse when I turn the headlights on.

I have ordered a 20Amp Noise Suppressor that i splice in between the + on the cigarette electric feed.

I am planning to place this behind the fuse board inside the dash under the steering wheel as there is plenty of room there. From the looks of this device i have to also connect it to a decent ground. Any ideas on a good place behind the dash? Or maybe there is a ground within the fuse board somewhere easily accessible?

If anyone has had any luck with one of these devices in the past i would like to hear from you with regards to your outcome.

Thanks in advance for your time.

Does it make interferance noises when its not on charge with the headlights on etc (signal lead pickup)? or it could be the phone itself generating the noise when its on charge as it could be chopping/inverting up the 5v to be able to charge the battery (high freq switch mode power supply). cheers - Stuart

The problem could very well be a ground loop as well.

It is very similar to when you plug say, a computer, into the aux port of an amplifier and get two different potentials across the two points, hence why you said it disappeared when you unplugged the power source.

Not sure if that filter does the same job as a ground loop isolator, but I suppose you can only try it.

The problem could very well be a ground loop as well...

+1

Easy to check...

Plug in the USB charge lead. Do you get the noise when you listen with headphones?

+1

Easy to check...

Plug in the USB charge lead. Do you get the noise when you listen with headphones?

Ok I'll check this tomorrow. If I don't get any buzzing what does it mean?

Also if I do get buzzing what does that mean?

Any chance you guys can watch this thread tomorrow for my reply?

Thanks

Ok I'll check this tomorrow. If I don't get any buzzing what does it mean?

Also if I do get buzzing what does that mean?

Any chance you guys can watch this thread tomorrow for my reply?

Thanks

If you still get buzzing, then the USB power adapter is faulty or of poor design. A good one rejects noise from the 12V supply.

If you don't get buzzing, then the USB adapter is good but you have an earth loop. If this is the case, you need to get the 12V from the back of the head unit.

If you don't get buzzing, then the USB adapter is good but you have an earth loop. If this is the case, you need to get the 12V from the back of the head unit.

Ok with headphones the sound is perfect whilst connected to the 12v USB. Guess it's a ground loop. I have a 57 plate octavia with a built in factory sat nav unit. Is there a 12v feed provided by this? If not will the 20amp noise suppressor not work?

What about one of these

Edited 13 June, 201115 yr by phillips321

Ok with headphones the sound is perfect whilst connected to the 12v USB. Guess it's a ground loop. I have a 57 plate octavia with a built in factory sat nav unit. Is there a 12v feed provided by this? If not will the 20amp noise suppressor not work?

What about one of these

Yes - it is described as a ground loop isolator so it should.