Does this work in removing the whiny noise upon acceleration? I installed aftermarket speakers via taping into the x9331 like what everyone is doing. Ran it through a LOC and back to JL 450/4 amp. Anyone tried ground loop isolator on this problem?

 

If you hear a high whine that is directly proportional to your acceleration, then a ground loop isolator will remove it. I used a 2.5mm isolator in my install, between my iPhone connector and the aux in.

 

Nope, bought it, tried it, didn't work. It even amplified the sound making it worst!
I tried hooking up the JL amp to my friend's alpine headunit and NO NOISE! Therefore, the problem is the Boost headunit.

 

This type of hum is usually caused by a ground loop I.E. that why it is named that way.

You can check a bad ground easily by taking a ground wire from the amp straight back to the battery and connecting it to the negative Outside the car temporarily. make sure you disconnect the groudn you have now. If this clears the probelm then the cause is probably some paint or corrosion in between the panels of the car not allowing for a good ground back to where you amp is currently grounded. If the body of the am is grounded then taek it off the pannel and put something in between it and the panel to eliminate that ground as well.

If this dose fix the problem then just run a ground wire from teh amp to the negative of the battery and hide it in the car.

 

This is very surprising - I've seen had a Ground Loop Isolator not fix the problem.

A few basic questions -

1) I assume you hooked it up between the head unit and the amp - did you ensure that the output of the headunit went to the input of the GLI and the output of the GLI went to the input of the amp? (to test this - I hooked mine up backwards and it did amplify the whine)
2) If number 1 is true - do you hear the noise when you play a CD? or is it only present when you play an external device like an ipod, mp3 player, etc.?

Can you describe exactly how it is hooked up - i.e. - using low level output of the head unit connected to low level inputs of amp via an RCA cable?

What schatzy62 describes is a permanent fix that should eliminate the the problem without the need for the isolator, so I'd definitely follow his advice if you can't get the isolator to work.

 

Check out this link:

http://www.termpro.com/articles/noise.html

Big help with diagnosing problems.

 

First off, I'd like to thank you for trying to help my frustrating problem.
I tapped into the x9331 and fed the signals into the L.O.C.. From the LOC, ran the RCA back to the trunk where my JL 450/4 sits. The remote for the amp is tapped into the trunk cigarret lighter. The amp ground cable is grounded into the rear driver's side panel. The power is run from the battery to the back via the passenger side, so the signals and power are on the opposite side. For the speakers, 6.5" 6kp Focals infront, 6x9 Focal Access in the rear. I used the polyglass crossovers and hid it in the arm rest. I think it's pretty standard setup.
One thing I've noticed is that the whinny noise get louder as I increased the sensitivity on the amp...
Turning off the Boost CD doesn't make the whine go away either. The sound is present when playing CD, radio or ipod (aux).
I might try that idea of running the ground from the amp to the battery negative terminal. I thought the shorter the ground the better?
BTW, I did try reversing the GLI and I still had noise. So it's going back to radio shack for my refund.

 

Don't for get to mention we used the rockford 360 v2 at first. However the sound was a hole lot worse. It seemed to amplify the problem. Also we tried diffrent amp, and the same problem was there.

The only time we didnt hear the noise was when it was hooked up to my alpine 9887 in my car, and when i hooked my archos 5 straight up to the amp via y cable (rca to 3.5mm jack).

 

Sounds like whatever the amp, headunit and LOC are grounded to are not the same potential (i.e. there is a small amount of voltage present on one or more of them at the ground) - This can me checked with an ohm meter set to the most sensitive setting. The ground on all devices should read zero. In your case - one (or more) of them should not be zero. Or - you can follow schatzy62's advice which should fix the problem. Does the LOC require a ground as well?

 

I belive it does not. Im sure the 360 did. But if this answers your question better. I tried hooking up rca directly from the x9331 conecter, and the noise was still there

 

When you tried the different amp, was it grounded to the same place?

I would suspect, based on the experimentation you describe here, that the potential difference is between the headunit which feeds the x9331 and the amp. You can try the ohm meter or just try what schatzy62 suggests - either one will answer the question, and making schatzy62's solution permanent should fix the problem.

 

same ground. Thats what im thinking that its the head unit itself that is casuing the problem. I guess this weekend or when we have time will try that out. Anyone have any other ideas that we could try please feel free to post

 

Grounding in cars is a very difficult thing to get around any paint or corrosion between panels of the car will cause slight differences in the ground potential and can cause many noise problems. This was very evident is the cars i owned as a teenager. Usually mid/late sixties cars with rust. Measure the voltage from the battery negative to the base panel of a trunk and you could get as much as 3-4 volts on something that should be ground. Go thru the car and de-rust or de-paint where the body panels touched you could get the problem to go away.

Yes the shortest ground is the best but if there is a problem causing it to not be EXACTLY the same potential as the battery Negative then it can cause a problem.

 

So you reconmend just basicly really sandind down that hole area basicly

 

I've wasted so much of my life chasing down ground loops that I started using a "star" grounding scheme. I run heavy-gauge cable from the battery negative terminal to a distribution block, and then *everything* in the audio system gets grounded to the distribution block - head unit, amplifiers, signal processors, CD changer, capacitors, whatever. It takes a little more time on the front side of the project, but it can potentially save hours on the back side.

 

I forgot to ask - does your line-out converter have fixed or adjustable output voltage? If it's adjustable, you may need to raise the output voltage on the LOC a little bit and lower the gain on the amp to compensate. Doing this obviously won't eliminate a ground loop, but it may make it inaudible.

 

i thought useing the ground on a battary wasnt reconmended

 

Although that is to some extent true, if as ScottRiqui said everything is grounded to the same point it eliminates the problems.

The most ideal situation would be to have all grounds go to the same place with the same gauge wire and all the ground wires be of exactly the same length but that is not at all practical. Theory and real world experience tell me that there is a ground problem. Trying to find the exact cause can be difficult. That is why i made the suggestions i did previously.

[/quote]You can check a bad ground easily by taking a ground wire from the amp straight back to the battery and connecting it to the negative Outside the car temporarily. make sure you disconnect the groudn you have now. If this clears the probelm then the cause is probably some paint or corrosion in between the panels of the car not allowing for a good ground back to where you amp is currently grounded. If the body of the am is grounded then taek it off the pannel and put something in between it and the panel to eliminate that ground as well.

If this dose fix the problem then just run a ground wire from the amp to the negative of the battery and hide it in the car[/quote]

 

I agree with schatzy62, if a ground loop isolator does not solve the problem, then it sounds to me like you have more than one pair of grounds at different potential. The only known, 100% sure place you have that is at true ground is the negative terminal of the battery (where that big grounding strap is). You can easily use an ohm meter to detect the offending ground(s), but fixing this will either involve schatzy62's recommendation or maybe MULTIPLE ground loop isolators. Just remember - electrically connecting multiple devices together without any noise interference assumes that they are all grounded at the same potential. Your best bet is to bring them all to the same ground point, using the same gage wire, even if they are different lengths. At a minimum, this will make it easy to measure and then GLI's could be used effectively to address the device(s) that is/are at a different potential. Unfortunately - this can sometime be a difficult thing to diagnose and fix. Good Luck and Happy Hunting!

 

the Voltage of our ground and the batty ground is the same. We tried to switch the rca, and LO. Which was reconmeded by a friend of my that owns a car audio store. however that did not work. After awhile we unpluged the rca, and the problem was gone. Even when driving around town. Then we conected my archos 5, and the problem was gone.Well there is some "data noise",but you cant hear it really its faint. So i think we might be just going to getting a aftermarket h.u in.