 | Home > In Car Electronics > Interference reduction? |
 
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731   
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Hi guys
Earlier this year I fitted several USB sockets powered off the lighter circuit. Two are for a TomTom iPhone cradle and an iPad. They work great but when I play music into aux from the cradle, I get rpm-dependent noise at higher volumes. Do you reckon fitting one of these: http://www.ebay.co.uk/itm/10A-NOISE-SUPPRE...4cefcf5a31 in the lighter circuit will work? I used one (just preventatively) for the powered sub "from new" so I have no idea if they really work. Cheers for any advice Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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21st Jul 2013 3:43pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610  
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At the price it's worth a punt anyway. We use similar on the boats and they do work.
 If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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21st Jul 2013 6:53pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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Cheers Mal - I'll give it a go
Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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21st Jul 2013 7:15pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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Matt,
Just remembered. Not so good I found if you're running a subwoofer or auxilliary/pre amp as they are that good it will suppress these too which defeats the object. If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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21st Jul 2013 7:26pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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Well, the radio/aux is run off its normal loom. Its speaker outputs are tapped to the sub, which takes its power (fused) from the battery with one of these gizmos in between. I guess the radio loom is already noise-reduced somehow.
The power supply for the cradles/phone/music is tapped from the lighter circuit, which I suppose would not normally need to be interference-free, i.e. it's very noisy! One thing I'm not sure about is where to earth the gizmo. Ideally it should screw to the bodywork but I wonder I I could tap onto another earth cable in there 
I admit ignorance about these electronic things, as normally whenever I try to change something, the rest gets worse. However, as you say, its only a few quid and worth a shot, especially if it works in some situations. Only real cost is the time to get the dash apart again 
Cheers Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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21st Jul 2013 7:54pm |
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| AndyS Member Since: 18 Aug 2012 Location: London Posts: 595 
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Do your speaker cables run past any of the main power cables for the car, the one that runs to the battery/from alternator? Seeing as there's no ignition system I'd guess it's alternator noise.
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21st Jul 2013 7:58pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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It's a weird setup, I guess - the aux doesn't normally have any problems with iPhones/mp3 players etc. The radio/aux and its cables seem to be okay. It's just when I use an iPhone which is being charged from the cradle/lighter circuit. As you say, I guess its alternator noise being fed (via the lighter wiring) into the aux. I'll try the gizmo and coaxial cable idea and report back
Cheers guys Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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21st Jul 2013 8:41pm |
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| WelshGas Member Since: 01 Oct 2010 Location: Vale of Glamorgan Posts: 935  
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I've got a similar problem, but I have wired a triple power and USB socket directly to the battery via a 20amp fuse and ignition switched relay. Definite engine/alternator speed related interference when using my iPod plugged into the USB socket and into the auxillary input on the Head Unit. So I'm interested as to how you get on!
LANDYWATCH
Neighbourhood Watch for Land Rover Owners http://www.landywatch.co.uk/smf2/index.php |
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21st Jul 2013 8:47pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17443 
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When I used to run a USB device powered from the lighter socket it suffered very badly from (what sounded like generator-induced) interference. Running a feed directly from the battery sorted the problem.
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22nd Jul 2013 8:15am |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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As mentioned previously using a 'screened' cable (something like SY perhaps if routing underneath the truck) and grounding out the screen should also prevent interference.
If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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22nd Jul 2013 8:22am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20442
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What Mal said above is well worth taking on board. The same goes for RCA cable too and if ever you have audio cables and power cables that have to meet ideally they should cross over at a right angle so that there is as little close contact as possible.
I know it involves perhaps a different HU or maybe even not possible to use your device in the way you want to but this is why I use a manufacturer made and "made for iPod" HU & cable which powers the device controls it and plays the music in one plug all running of the HU. By charging via an external USB and playing via the 3.5mm audio jack you are creating an electrical loop inducing interference noise / electrical noise. (happy to be corrected on this though) Also make sure the audio jacks are fully inserted as that can cause some noise and also perhaps try a different cable for the sake of it. $W33T $0U7H3RN $UG4R
🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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22nd Jul 2013 10:28am |
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| Grockle Member Since: 24 Nov 2008 Location: Peak District National Park Posts: 2266 
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Where do you wire into,on ours when you select reverse aload of interference comes through the speakers 2.4 90 XS
1968 1/32 scale Britains 109 Pick up. |
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22nd Jul 2013 11:10am |
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| barbel jim Member Since: 12 Dec 2012 Location: Northants Posts: 1423 
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Earths are the first place to start. the shorter the better and more effective. I would also check your getting 12+ volts out of your sockets, especially when they are all in use. Someone else has already said they wired them separate which seems like a good idea as well as maybe solving the problem.
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22nd Jul 2013 12:10pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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I get exactly the same with the standard radio setup and I am 100% sure it comes from the (cheap) LED reversing lamp I installed. *UPDATE* 1) First it didn't work... 2) Then it did
1) The cradles are powered from the lighter terminals so I put the noise-filter between the (+) lighter terminal and the (+) cradle, earthing it to the body via this fuse holder stud: [URL=] Click image to enlarge[/URL] However, it only cut out 50% of the noise
2) Then I realised I was still using the (-) lighter terminal as earth for the cradle - probably still a source of noise
So I took the cradle (-) to the same fuse holder stud and Bingo! Hardly any noise now - my classical collection can again be heard
Finally, proof of my trust in 3M Velcro: [URL=] Click image to enlarge[/URL] Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated  Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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28th Jul 2013 5:36pm |
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