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Thread: Interference through headunit Please Help!!!

  1. #1
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    Interference through headunit Please Help!!!

    I have a really strange problem thats been doing my nut for about a week now!

    Really need some help from the experts on this one.

    I have fitted a new headunit, which is a motorised tft screen - It works perfectly apart from when the engine is running then i get constant ticking followed by a whining that get's higher in pitch as i rev.

    I can't try a ground loop isolator with the indash screen i'm using at the moment as it connects directly to the ISO block like a normal headunit.

    I did try one with the amp and it was slightly better but still there.

    I'm totally confused as to how its happening this is the situation to where i am at the moment:-

    Alpine CD Player - Removed (worked perfectly even with engine on)

    4ch Amplifier and In dash Screen - Removed (ticked and whined when engine on, thought it was a faulty amp/screen)

    Different In dash Screen with built in amp - Fitted (Same ticking and whining experienced with standalone amp)


    I have tried:-

    Earthing in dash screen to body instead of ISO block (no difference)

    Powering direct from battery while earthed to body (ticking quieter - whine still there)

    Halfords in line power interference suppressor (no difference)

    Fitted Halfords alternator noise suppressor on to the alternator (no difference)


    I don't understand why its doing it - the alpine works fine as I've retested it. But the seperate amplifier and the indash screen both pick up interference!

    Please can a knowledgable bod help me before I tear ALL of my hair out!!

  2. #2
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    Quote Originally Posted by swift_gti View Post
    I have a really strange problem thats been doing my nut for about a week now!

    Really need some help from the experts on this one.

    I have fitted a new headunit, which is a motorised tft screen - It works perfectly apart from when the engine is running then i get constant ticking followed by a whining that get's higher in pitch as i rev.

    I can't try a ground loop isolator with the indash screen i'm using at the moment as it connects directly to the ISO block like a normal headunit.

    I did try one with the amp and it was slightly better but still there.

    I'm totally confused as to how its happening this is the situation to where i am at the moment:-

    Alpine CD Player - Removed (worked perfectly even with engine on)

    4ch Amplifier and In dash Screen - Removed (ticked and whined when engine on, thought it was a faulty amp/screen)

    Different In dash Screen with built in amp - Fitted (Same ticking and whining experienced with standalone amp)


    I have tried:-

    Earthing in dash screen to body instead of ISO block (no difference)

    Powering direct from battery while earthed to body (ticking quieter - whine still there)

    Halfords in line power interference suppressor (no difference)

    Fitted Halfords alternator noise suppressor on to the alternator (no difference)


    I don't understand why its doing it - the alpine works fine as I've retested it. But the seperate amplifier and the indash screen both pick up interference!

    Please can a knowledgable bod help me before I tear ALL of my hair out!!
    What is your audio source. Is a carputer connected to the headunit. A little bit of information about how your car and audio system setup would help tremendously. Also, there is a very informative and lengthy post/thread regarding this noise. Do a search.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

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    Sorry I knew there was something I forgot!!

    This is with no source connected at all.
    It simply the Lilliput touchscreen (has its own amp built in) connected via the ISO connectors on my car to my standard speakers (2 sets of components)

    Same when I tried the standalone amplifier - no source connected still got ticking - but I only got the whining with a source connected on that one...

    I have searched but I only seem to find things about moving to a better earth point - but I've already sanded down the bodywork and used a self tapper to make a clean earthing point.

    I'm at a loss to what I can try to fix this now!

  4. #4
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    You're more than likely getting feedback from the backlight inverter if you're using something built into the screen.

  5. #5
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    Quote Originally Posted by swift_gti View Post
    Sorry I knew there was something I forgot!!

    This is with no source connected at all.
    It simply the Lilliput touchscreen (has its own amp built in) connected via the ISO connectors on my car to my standard speakers (2 sets of components)

    Same when I tried the standalone amplifier - no source connected still got ticking - but I only got the whining with a source connected on that one...

    I have searched but I only seem to find things about moving to a better earth point - but I've already sanded down the bodywork and used a self tapper to make a clean earthing point.

    I'm at a loss to what I can try to fix this now!
    K, I am no expert, but I will do what I can.

    First, Do you get the whine with out using the "other/external" amp you mentioned. So, when just the Lilli built in amp is powering the speakers?

    There are devices that are meant to go in the power wires to eliminate engine whine. You mentioned you used something, I just want to confirm that is the type of device you used, NOT ONE FOR THE AUDIO PATH, but the power wires. Also, can you try a different brand if in fact that is the type of device you used. You also might try putting the filter on the "accessory" wire in case it is introducing the noise.

    It is possible that the quality of the internal amp is just not good.

    Can you try powering the unit with heavy gauge wire directly from the battery, including the accessory wire for testing purposes.

    Have you tried earthing the BODY of the unit. Maybe something in the car is causing the interference, and the Lilli is just not adequately shielded. Try wrapping the unit in aluminium foil (MAKE SURE NOT TO LET IT TOUCH ANYTHING WITH POSITIVE POWER ON IT) and see if that improves the noise.

    Hope some of that helps.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  6. #6
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    Thanks for the suggestions Michael,

    I do get the whine with the external amp (ie. just your usual car amplifier) but only with a source connected - I do get the ticking though, even with just the amplifier powered and the engine running.

    I have indeed tried an inline device for the power wires not the audio lines (can only seem to find RCA type ones - my unit connects by standard speaker connections, no RCA's involved)

    Forgot to mention I tried using the amp power lead (thick gauge straight from battery) and connected it to the Batt & ACC line on the Lilli just to test - the ticking was quieter but the whine was just as bad....

    I will try and test the foil method and see what happens...

    Cheers

  7. #7
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    Quote Originally Posted by swift_gti View Post
    Thanks for the suggestions Michael,

    I do get the whine with the external amp (ie. just your usual car amplifier) but only with a source connected - I do get the ticking though, even with just the amplifier powered and the engine running.

    I have indeed tried an inline device for the power wires not the audio lines (can only seem to find RCA type ones - my unit connects by standard speaker connections, no RCA's involved)

    Forgot to mention I tried using the amp power lead (thick gauge straight from battery) and connected it to the Batt & ACC line on the Lilli just to test - the ticking was quieter but the whine was just as bad....

    I will try and test the foil method and see what happens...

    Cheers
    K, have you tried the audio Ground Loop Isolator between the Lilli and the external amp? How did that work?

    Clicking is different. That tends to lead me to either something in the car causing some sort of interference, or that the electrical system/batter/alternator of the car has a problem. Can you get them checked out?

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  8. #8
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    your problem is that the ground on your alternator does not have the same resistance as a ground on your radio or amp. try regrounding either or both on various points and see if it goes away.

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