Interference Using 910 MP3 Player

edjharris · Occasional Visitor Joined: May 21, 2006 Posts: 2

Hi everyone,

I've been having problems with interference when using the MP3 player on my GO 910 while connected to my car stereo.

I get static and electrical "fuz" noise when I accelerate. It's not too bad when listening to music (though still annoying), but it can make speech MP3s impossible to listen to.

Through trial and error, I've worked out that it must be something to do with the power cable, as I don't get the problem when I'm running the 910 off its battery.

It seems the power cable is picking up the electrical signals from my car's engine when it's running. They are always there in the background, and get much louder when I accelerate. I have a VW Golf MK4 if it makes a difference.

I was wondering if anyone else had had this problem, and if anyone has found a workaround? Is it possible to get shielded power cables for example?

Thanks,

Ed

mikealder · Posted: Fri Jun 09, 2006 6:51 pm Post subject:

Ed, does the interferance increace with engine revs? if it does I would suspect the supression unit on the alternator, or the HT leads to the spark plugs (if fitted - it could be diesel powered) - either way the simple answer is to fit an electical noise supression device to the cigy socket powering the TomTom unit, its a simple fit soldering a capacitor across the terminals of the socket - check out your local Maplins store for advice, or possibly Halfords (but I suspect they won't know what you are talking about) - Mike

edjharris · Occasional Visitor Joined: May 21, 2006 Posts: 2

Hi Mike,

Thanks for your reply.

Yes it does increase with engine revs, so it sounds like your thoughts are correct.

The car is a diesel by the way.

Could you tell me exactly what to ask for, or point me to a good website, as I don't have much idea about this stuff at the moment?

Thanks for your help,

Ed

mikealder · Posted: Fri Jun 09, 2006 7:33 pm Post subject:

It is most certainly the alternator output that is causing the noise, the alternator will be fitted with a noise supression unit, but these can break down,, they only cost pennies, so find a local Automotive electical workshop, or a decent automotive accesory shop, and let them deal with the problem, You are better off eliminating the noise at source rather than filtering the noise at the point of conection - Mike

duttonst · Occasional Visitor Joined: May 28, 2006 Posts: 12

The 910 does seem to be exceptionally sensitive to this type of noise. I had *exactly* the problem you describe and luckily found someone in Halfords who actually knew what they were talking about.

I ended up buying a ground-loop isolator - about 15 quid - which is very easy to wire-up (2 phono in, 2 out, no soldering). It's completely solved the problem for me.

Hope this helps,

Andy

Eldar · Posted: Sat Jun 10, 2006 11:08 am Post subject:

Where exactly did you fit the ground loop isolator? As far as I understand it would only work if you are using the audio out from the GO910.

duttonst · Occasional Visitor Joined: May 28, 2006 Posts: 12

Before fitting the isolator I had the audio-out of the 910 directly connected to my car stereo via an fm modulator (although I'm not sure if that's relevant). I connected the isolator in between the 910 and the fm modulator - it took a few seconds.

You mention your 910 is connected to your car stereo but you don't mention how....are you somehow doing this without using the audio out cable?

BTW, I've seen a number of posts on this issue and I think there may be a bit more to it than faulty alternator noise suppressors. My car is pretty new and I've connected a number of other audio devices to it without this problem. The 910 does seem to be very sensitive.

Cheers,

Andy

Eldar · Posted: Sat Jun 10, 2006 12:06 pm Post subject:

did you have this problem when listening through the internal speaker?

duttonst · Occasional Visitor Joined: May 28, 2006 Posts: 12

Don't remember....except that the quality through the internal speaker wasn't exactly brilliant.

Eldar · Posted: Sat Jun 10, 2006 1:38 pm Post subject:

If edjharris is having this problem when listening to MP3s on the internal speaker, the isolator is not going to help and he'll need a noise supressor on the DC feed.

duttonst · Occasional Visitor Joined: May 28, 2006 Posts: 12

True, but he said it was connected to his car stereo :D

Eldar · Posted: Sun Jun 11, 2006 1:08 am Post subject:

So he did - I missed it, my apologies. The isolator it is then.

AVRHack2 · Occasional Visitor Joined: Dec 27, 2006 Posts: 24

Same problem for me - what convinced me it wasn't the TomTom's output per se is if you plug in a set of headphones directly to the TomTom's external jack - on mine the quality is then first class with no noise whatsoever.

Worth a try before doing the 'ground loop thing' as it will confirm whether it is a ground loop problem or something else.

mikealder · Posted: Fri Dec 29, 2006 10:56 am Post subject:

Easy to get hold of now and less than £10 see HERE - Mike

AVRHack2 · Occasional Visitor Joined: Dec 27, 2006 Posts: 24

Mike, you're a superstar! Was going to go to Halfords and probably pay £25, or solder one up myself instead.

£9 now from good old Maplin - and your POI file shows me the nearest one - not that I didn't know where it is of course LMAO!

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