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    GLI - Live With It???

    Ok, I have a ground loop problem and the only solution that seems to work is to use a Ground Loop Isolator hooked up to the RCA's on the amp. I just got the system installed recently and took it to 2 different shops and they were both not able to fix it. I went to the first store where I had purchase and installed my system. After having the car for the whole day, they were unable to solve the problem without using the GLI.

    I did an A/B comparison with the GLI on and off and the difference was night and day. With the GLI on, the highs was harsh and the lows were muddy at higher volume levels. With the GLI off, the sound was completely clean on the highs and lows while playing at high volume. This really kills me since I am forced to use the GLI and compromise the SQ.

    The noise is classic alt whine. Its only there when the engine is on and the pitch changes when the gas pedal is pressed. The noise is very faint and one shop even went so far as to suggest its "acceptable"! I can tell its there though and it drives me nuts.

    One shop I went to, we replaced the RCA's with $100 monster cables. We first ran it over the car seats and carpet and the noise is gone. When they ran the cables underneath the carpet the noise came back! So I ended up just using my existing RCA's.

    The other shop where I left my car for them to work with did a lot of things that one would do to get rid of ground loops i.e. ground at amp, deck to batt. neg. grounding rca to chasis, moving deck ground to behind dash, disconnecting antenna cable, switching decks, etc. They pretty much did everything but one thing that interested me was that they said they used their highest quality RCA running over the seats and carpet and with the Deck outside of the dash and the noise was still present.

    The only other thing I can think of is to do the Big 3 upgrade or 2 out of the 3 which are: Battery negative to Chasis and Engine block to Chasis. My installer said that with my system it won't help so they didn't do it.

    What do you guys think? Should I just live with a compromised system? Will upgrading 2 out of the Big 3 make a difference? If there is anyone living in the 808 state that is willing to take a look at my car and help me out, I would really appreciate it.

    My system is pretty simple:
    2005 CR-V
    Alpine 9835
    Rainbow SLC 265
    Stock Rears (powered by HU)
    ARC 12D2 Sub
    ARC 4150-XXK (powering rainbows and arc sub)







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    Re: GLI - Live With It???

    did you reground ur headunit and make sure everything has a common ground? your amp could be broken or your deck. maybe a bad rca ground on one of them. Id suggest finding a friend with an alpine that can you can switch with and see if its the deck and then switch amps with someone and see if its the amp. You could also try plugging the rcas into the rear preouts ( i assume you have them coming out of the front since the one amp is powering both sub and speakers.)


    Do you hear the whining out of the rear speakers?

    I had altenator whine and i replaced my RCA's and it went away and never came back.




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    Re: GLI - Live With It???

    Quote Originally Posted by kuijo
    did you reground ur headunit and make sure everything has a common ground? your amp could be broken or your deck. maybe a bad rca ground on one of them.

    I had altenator whine and i replaced my RCA's and it went away and never came back.
    Yes, they tried regrounding the HU to behind the dash. They even tried grounding to the same ground as the amp. They also tried grounding a piece of wire from the RCA shield to the HU chasis. The amp is not broken, my installer put in a new amp. The deck is not broken, I bought it brand new and we tried putting in my old deck and the noise is still there.

    The 2 shops I went to tried to replace the RCA's and the noise is still there. I think I'm going out of my mind

    Next thing to do is the Big 3 but I don't know if it will solve a ground loop problem.




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    Re: GLI - Live With It???

    What size ground and power wire is the amp running on?
    Are the rcas running on the same sides as the power wire?




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    Re: GLI - Live With It???

    Quote Originally Posted by kuijo
    What size ground and power wire is the amp running on?
    Are the rcas running on the same sides as the power wire?
    I'm not sure what size, I have to take a look at the car when it gets back here but it looks pretty beefy. The RCA's and the powere wire for the amp are running on opposite sides of the car. The noise is definitely coming in from somewhere in the HU or in front of it.

    If we unplug the RCA's on the amp, the noise is gone. If we put it in the GLI on the amp the noise is gone. So this must mean that the ground loop is at the HU? But we have tried every single fix mentioned but we are still getting alt whine.




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    Re: GLI - Live With It???

    This link is based on home audio but the principals are the same-
    http://www.epanorama.net/documents/g...oop/index.html

    Here is some extra info cut and pasted from rec.audio.car FAQ

    2.1 My speakers make this high-pitched whine which matches the engine's
    RPMs. What is it, and how can I get rid of it? [IDB]
    ================================================== ========================

    The answer to this section was generously provided by David Navone of
    Autosound 2000. The material in these instructions was adapted from
    the Autosound 2000 Troubleshooting Flow Chart by Ian Bjorhovde with the
    permission of Autosound 2000. For more information about Autosound
    2000, (see Section 7).

    This is a set of instructions to debug a stereo installation if there
    is any noise present after it is completed. Follow each step
    carefully! If you have more than one amplifier, repeat level one for
    each amp to be sure that none of them are responsible for the noise.

    2.1.1 Level 1: Check out the Amplifier(s)
    ------------------------------------------

    After you have determined that there is noise in the system, determine
    if the amplifier is causing the noise. To do this, mute the signal at
    the inputs to the amp by using shorting plugs. If there is no noise,
    then the amp is fine, and you can proceed to level 2. However, if
    there is noise, then use a test speaker at the amp's output. If this
    stops the noise, then the problem is originating in the speaker wiring,
    or the passive crossovers. Check to make sure that none of these are
    shorting with the body of the car, and start again at level 1. If
    noise is still present when using the test speaker, then there may be a
    problem with the power supply on the amp. Try connecting an isolated
    power supply - if this does not get rid of the noise, then there is
    something seriously wrong with the amp, and it should be replaced. If
    the noise goes away, then there may be a problem with power supply
    filtering or isolation. This can be fixed by changing the amp's ground
    point or b adding external supply filtering.

    2.1.2 Level 2: Reduce the System
    ---------------------------------

    The amps have been determined to be noise free. If you have any
    processors between the head unit and the amps, disconnect them and
    connect the head unit directly to the amp. If this gets rid of the
    noise, then one (or more) of the processors must be at fault, so
    proceed to level 5. Otherwise, try running the signal cables over a
    number of different routes. If you are able to find one that does not
    produce any noise, permanently route the cables in the same manner, and
    proceed to level 5. If not, then you must isolate the head unit from
    the car's chassis (except for its ground!) - don't forget to disconnect
    the antenna, since it is also grounded to the car. If isolating
    the head unit does not solve the problem, the move the grounding point
    of the head unit. Hopefully the noise will be gone, and you can
    install the head unit with a quiet ground and proceed to level 5,
    otherwise go on to level 3.

    2.1.3 Level 3: Move the Head Unit
    ----------------------------------

    The amplifiers are fine, but moving both the ground for the head unit
    and the signal cables does not solve the noise problem. Take the unit
    completely out of the dash, and put it on either the seat or carpet,
    and run new signal cables to the input of the amp. If this solves the
    problem, re-install the head unit, one step at a time and skip to level
    5. But if the noise persists, then move the head unit as close to the
    amp as possible and use the shortest possible signal cables. This will
    verify that the original signal cables are not causing the problem -
    assuming the noise is gone, reinstall the head unit one step at a time
    and go to level 5. Otherwise, there may be a problem with the power
    filtering for the head unit. As with the amps, power the head unit
    with an isolated power supply (again making sure that the head unit
    isn't touching the car's chassis at all). If the noise goes away, you
    can add power supply filtering or an isolated power supply; go to
    level 2. But if the isolated power supply does not solve the problem,
    then you can either replace the head unit and go to level 2, or check
    the car's electrical system in level 4.

    2.1.4 Level 4: Testing the Car
    -------------------------------

    There does not seem to be a problem with either the head unit or the
    amplifier, and the car's charging system is suspect. To see if this is
    the case, we can use a system in a car that is already known to be
    "quiet." Bring both cars together as if you were going to jump one,
    and use jumper cables to connect the two batteries. Start the engine
    of the car with the noise problem, and listen to the "quiet" car's
    system. If the noise does not go away, there is a SERIOUS problem with
    your car's electrical system (possibly a bad alternator). Have a
    qualified mechanic check the charging system out. If there is no noise
    in the "quiet" car, then the "noisy" car's charging system is
    definitely quiet, so continue with level 5.




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    Re: GLI - Live With It???

    Con't-

    2.1.5 Level 5: Adding Signal Processors
    -----------------------------------------

    We have proven that the amplifiers are good, the head unit is good, and
    the car's electrical system is good. Now we need to reconnect each
    signal processor. Repeat this level for each signal processor used in
    your system; if you have added all of your signal processors, and
    there is no longer any noise, CONGRATULATIONS! You've removed the
    noise from your system! Connect the signal processor. If there
    isn't any noise, then go on to the next signal processor. Otherwise,
    try re-routing the signal cables. If this cures the problem, the route
    them permanently over the quiet path, and install the next processor.
    If not, then isolate the processor from the car's chassis except for a
    single grounding point. If this works, then permanently isolate the
    processor, and move on to the next processor. If isolation does not
    help, then advance to level 6.

    2.1.6 Level 6: Processor Isolation Tests
    ------------------------------------------

    Now, noise enters the system when one particular processor is
    installed, but regrounding it does not help. Move the processor very
    close to the amp, and check for noise again. If there isn't any, then
    re-install the processor, carefully routing the cables to ensure no
    noise, and continue at level 5 with the next processor. Otherwise, use
    an isolated power supply to power the processor, making sure that no
    part of the processor is touching the car's chassis. If this solves
    the problem, the consider permanently installing an isolated power
    supply or possibly a 1:1 transformer, and go to level 5 with the next
    processor. Otherwise, separate the processor and isolated power supply
    from the car by many feet and re- test. If there is still noise, then
    there is a serious problem with the processor's design. Get a
    different processor, and continue at level 5 with it. If separating
    the power supply and processor from the car does solve the noise
    problem, then either the processor is damaged, or your tests were
    inaccurate. Repeat level 5.




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