interesting noise problem

I would put this in ground noise but I am not sure where to head now..Problem started long ago

When I plug both front and rear RCA's into my 4 channel I get a whine, alternator whine... If use a y splitter and run rear or front to both sets of inputs no whine..

I though rca's...Replaced them   Same thing
Though rca location..I have even tried duct taping them to the celing!   still whine

So I though deck, Re grounded the deck to about 4 diffrent spots..each one same amount of whine.
Changed the deck to a new model..same thing

Thought it was the EQ..regrounded..whine...eliminated it out of the system..still whine

Though it was the cheap amp I was using..Bought a diamond audio 600.4    same thing..but slightly better, I mean very very slight

Though maybe battery, fliud full. charge full, battery tested OK

I have regrounded every component in the system and also changed almost all the components

ANY SUGGESTION????????

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

I just though of it, Maybe I should try regrounding the battery..and alternator????    Just a thought

Also if any SQ guys have any advice on helping noise floor that would be great.   Before I run the car in sq, I think the 2.5 volt output deck I have needs to be replaced, I think that would help my noise floor isues

For those who dont know Noise Floor is.. When you play a blank track on your cd and you can max the volume and hear a hissing or poping noise..I personally have a strong hissing noise

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

I hate to say it Jeff but it sounds to me like you have a head unit with an inferior preamp and that the ground plane on the two outputs (front and rear) are unequal.  So you are hearing the ground loop caused by the differences between the two line-level signals.  This is actually common in cheaper consumer-level heads.  If you have a good multimeter, check for resistance between the ground rings on the preamp outputs, or voltage between the rings during operation.  It should be less than 0.1 ohms and/or less than 1mv.

Voltage output is less important in creating a better noise floor than is a quiet preamp.  Look at the S/N ratings on your head.  World-class performance is in the neighborhood of 100db.

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I know this might sound weird but try connecting the grounds on the rca's together. I have done this before on hu's that had this same problem. Beleive it or not it took care of the problem.

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hmmm I might have to try that.    did you just ground the 2 rca sets FRto RR and FL to RL   or did you connect them like that and also ground the rca's as well??

As far as the deck I know, I should be running a far better deck for the eqipment I have..I am running a panisonic 5310   Actually it is one of the better built in eq's I have used, lets you fully adjust 8 frequencys. I will be starting to look into eclipse and other high end decks, but I love the ease of use that all the panisonic decks have.

Does anyone know of a deck that has a fully adjustable EQ in more then 8 bands built into the deck, and will truly work??

Here is a list of the current equipment
panisonic 5310
power acoustic dvd
2 5.6 inch screens
memphis hc50 sub amp
diamond 600.4 internal
alpine 6.5 type r comps
memphis 5.25 co-ax
eclipse aluminum 10's


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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

You could try connecting the outer rings of front and rear pre-outs together, but be sure to try this with the head OFF!  You run the risk of destroying both preamps... but if your head has that much voltage differnetial between them, perhaps it is time to trash it anyway.  The best logical step up for you would probably be an Eclipse.  Don't be too stuck on replacing the Panasonic EQ (which is good, I agree) because in a properly setup vehicle you really shouldn't need it, but if you like EQs the new Eclipse 5444 might tickle your fancy.

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i will be sure to check into that, If i wanted a tempory fix would you recomend grounding the front and rear rca's together?   I havent done this, and sounds like trouble to me,   If i hook them up with the head unit off, as soon as I turn it on wont there be problems?

Like I said I really like the ease of use of the panisonic decks and the eq feature as well, But I am more then willing to go to an eclipse deck,   What do you think of the Alpine d300?   do you think will surfice for a good sq deck?

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

Yes just connect the ground of both rca's together. Then you can power the hu. There should not be any problems doing this. Like I said I have done this several times without any incidents.

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One other thing this is by no means a fix it will just help you isolate the problem. I would not recomend doing it for a long period of time. Not that you did not know this!

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well I will try it out sometime this week, It is raining today and really dont want to get out and work on it at the house.   Besides its sunday and football is on....Go Lions!

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

 i notice i'm a little behind here and you've prob got your probs fixed but i'll ad my 2 cents anyway, how's the alternator? is there any ac current  along the power wires and the grounding for the the vehicle itself deicent? i'm no pro at this  but it's like i said..my 2 cents  

everything in the charging system has been gone through,   I think its just time for a stronger deck,   thinking of the alpine d300   whats everyone think?

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

It seems like a decent deck. You do realize that it also has 2v outputs on it. Have you looked @ the Eclipse or Nakimachi ( spelling sucks I know)?

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i currently looking into diffrent units right now, trying to find a DVD/Screen combo that has 5-6v outputs

I will have to wait now as my amp started acting up today, need to replace the rca jacks, they are shot

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place