/ Strange van electrical problem

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Gav M - on 24 Dec 2013

I have a strange electrical problem in my van.

For music in the back of the van I have a car stereo running off the leisure battery.

When used as radio or CD player the stereo functions normally.

When I line in an iPod using a 3.5 mm input the sound is not right, completely unbalanced and lacking bass.

When I plug the iPod into a 12 V socket to charge the sound becomes normal again.

Simply contacting the iPod charger to to the van body also restores the sound to normal.

Clearly it is an earth issue of some sort, but what exactly is going on?
gethin_allen on 24 Dec 2013
In reply to Gav M:
A damaged audio lead sounds most likely.
Have you tried a different audio lead or tested the audio lead on a different stereo?
Gav M - on 24 Dec 2013
In reply to gethin_allen:

The audio lead was my first thought too, so I ordered a new one.

The problem is the same with a brand new lead.

Additionally the problem is the same whether I use an iPod or a phone.

Perhaps the finger of suspicion should now point towards the input socket on the stereo. If the input socket is indeed damaged what could I do to fix it?
Gav M - on 24 Dec 2013
In reply to Gav M:

Input socket looks fine.
gethin_allen on 24 Dec 2013
In reply to Gav M:

Without sounding daft, does the lead fit all the way in? I've had problems with the plastic coverings on phono plugs preventing the plug fitting into recessed sockets, so ,such so that I doctored a cable to fit.

Otherwise it's likely a soldered joint has failed and you'll probably find that there is so much stuff squeezed into a car stereo it will be impossible to get at the joint to fix it.

If you gently wiggle the plug in the socket do you get any better sound.
Gav M - on 24 Dec 2013
In reply to gethin_allen:



Wiggling has no effect and I took the front of the stereo apart to examine the contacts on the jack plug - it definitely fits right in and contacts properly.

If you're right about the soldered joint then at least I have a workaround in that earthing the iPod through its charging cable gives me decent sound quality.

In fact come to think of it the sound from the aux input has always been mildly substandard - when I installed it I compared the same piece of music on CD and mp3 and the CD was much richer, so perhaps this is just the final stage in the failure of a joint that has always been suspect.

To be clear on your proposed root cause, are you suggesting that the joint in question is part of the circuit that connects the shield part of the audio cable to earth, and that I am able to re-establish a connection to earth via the charging cable?
gethin_allen on 24 Dec 2013
In reply to Gav M:

Yes, that's what i'm thinking.
peebles boy - on 24 Dec 2013
In reply to Gav M:

I had something similar with iPod and old cassette deck in van. Fixed by turning the volume down a bit on the iPod itself, and up a bit on the van's cassette player.

Don't know why this happens, or why the above volume control fiddle fixes it, but there you go!!
Gav M - on 24 Dec 2013
In reply to gethin_allen:

Thanks for your assistance, I was completely perplexed this morning but now I'm happy that I understand what's going on.
climber david - on 24 Dec 2013
In reply to Gav M:

Along the same lines of gethin allen's suggestion, does the plug fit into the ipod alright? I've had a couple of problems when the source has been in a case

David
BStar - on 24 Dec 2013
In reply to Gav M:

It could be a ground loop problem, you could try a ground loop isolated cable, I picked one up the other month from amazon, a Kingston one for under 10. I had a problem with a really low volume, it could be a similar problem to yours, especially if plugging it into 12v corrects it as it then shares the same ground.
Gav M - on 24 Dec 2013
In reply to BStar:

Hadn't heard of ground loop cables, cheers for the tip.

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