My weird experience with alternator whine (Alpine HU)

[Sam Kapasi]

So here’s a weird experience I had.

Alpine HU, 2 amps, Van den Hul RCA, 2 different kinds (silver for front and carbon hybrid for rear), wonder-solder and terminated with neutrik.

Right from day one, I’ve had this barely, just barely audible alternator whine from all my speakers. It’s not annoying, just can be heard if you concentrate hard on empty passages during the music. In fact most people wont hear it.
I have always attributed it to the fact that in effect I’m using home audio cables(no matter how good they are) and perhaps the shielding may not be as strong as a car-dedicated cable and hence the ground loop/whine rejection may not be at par with some cables more desgned to reject in-car interference.

So, I’ve been good with this setup for a year almost.

3 days ago, in a hurry to get into office (drove from pune) left the headlights on all day by mistake. Needless to say, the battery (amaron) was as dead as a doorknob on my return. Called my local chap, who arrived forsooth, with a spare battery (exide).

Hooked it up, took my amaron and left. I drove off. To my complete annoyance, the alternator whine was now really loud. Like atleast twice or thrice as much. Like LOUD. And would get louder when the AC was on.
I was confused and quite depressed. Didn’t have time to do anything about it, except curse on my way to office and on my way back.
Today my battery returned. Plugged the amaron back in and voila – things are back to the way they used to be. Now how about that. To get it straight, I plugged the exide back and WHEEEEEEE, remove the exide, put the amaron in and it’s just fine.

So that’s weird. 2 identical spec batteries. Now let’s hear what you have to say

[a4_attitude]

sam aftr reading must say keep your fingers crossed
Wadhwa Ajay

[navin]

Originally Posted by Sam Kapasi

So that’s weird. 2 identical spec batteries. Now let’s hear what you have to say

wont be surprised if this has to do with battery resistance. Are you sure these are identical batteries? I'd like to see ALL the specs on both these batteries. alternator whine is related to the DC resistance between the alternator and the negative post of the battery. i would check the exide to see if all cells are ok and if the terminal posts are clean.

[Rudra Sen]

But Navin, alternator whine was there..may be very little....

How to eleminate that totally? Because I also have it..

[Sam Kapasi]

Originally Posted by Rudra Sen

How to eleminate that totally? Because I also have it..

Oh Rudy,

That has been an eternal struggle.

1) Make sure that the power cables and audio cables arrive to the amplifier from different sides
2) Make sure you use a high grade Audio cable
3) Make sure your amp gains are not too high

Beyond this, there is a little circuit called a "ground loop isolator" a little concoction made of little isolating transformers. This will 99% get rid of the whine. Most will find it fine, but some will claim that it degrades the sound a bit.

[Rudra Sen]

Originally Posted by Sam Kapasi

1) Make sure that the power cables and audio cables arrive to the amplifier from different sides
2) Make sure you use a high grade Audio cable
3) Make sure your amp gains are not too high

Oooh my god Not again.....Not again

[Sideways]

And if all else fails theres always Aliminium Kitchen Foil - Thanks you Navin (Take A bow please Sir).

[low_bass_makker]

Sam bhai and Rudra sir before going forward here are some help from my side...

firstly Sam bhai I think about ur strange experience is could say like navin ji said the battery internal resistance would be the culprit . the battery used could be a service battery with a little less electoyte than the normal which could have changed the internal resistance...like u said that when the amron was installed back the noise went back ...it can be verified by putting the exide back fill it with distiled water to top up the level....and charge it fully and then see that the noise is there or not...

rudra sir a little about the noises in the ICE....

It can be check by powering up the system from a external power like a battery and all the things even the hu amp every thing....then start the engine and see that there is noise or not ...if it is still there then problem lies some place else....if it goes away then the problem lies in the power wiring...to rectify it we need to connect back every thing one by one starting from amp which are less prone to this type of noise problem....if it comes back u need to put a noise suppressor in the path of the power supply to solve it.....if the external power supply test did not helped then no noise suppressor could help u in this case....make a shorted rca leads (take rca plug and short the both ends in the plug) connect it the amp input which make the amp to behave like there is no input there ...after that check if there is some noise or not if it is there then the amp is fault....replace the amp to verify that .....or even changing of the earth connecttion could help a lot....now one thing more the RCA leads could be the culprit also try replacing them can also help......the final thing take out the hu from the mounting place where it is installed while it is running...check that the noise is still there or not ....if it goes away the u have to shift the HU or try to ground it from any other place.....hope this helps....

in my last few installs which have been done in the following car like maruti 1000,zen,accent viva,swift...in all the above cars I did not have a single problem of any alternater whine....in these install all the bunch of wire which include

1) main power postive from battery
2) remote turn on
3) front speaker wire 2 pairs
4) rca wire x 3nos

all run together...but no noise what so ever....to prove it I can even post pics of the same....

like navin ji said the alternater noise comes in the system when the gorund is taken from differnt points which make a potential difference between them which inturn comes out to be the noise in the system..

[mohit]

to prove it I can even post pics of the same...

Pictures of the Wires or whine?

[low_bass_makker]

Originally Posted by mohit

Pictures of the Wires or whine?

the pictures of the wires and the clean sound without the whine.....

[hydrashok]

Sam, I had a similar experience about a year back. Same brands of batteries. My Palio was running an Exide (the stock one that came with it), and I thought there was a very light whine in the empty/almost empty spots in the music. I didn't know where the whine had come from then, and I thought it was the cabling. My A/c had had some problem, and had dumped water into the car floor during a long drive, and the carpet was soaking wet for a day or so till I got it fixed at the service center. my power wires run thru the middle (gearbox?) hump, and hadn't got wet. The RCAs and speaker wires run through the sides (just under the doors) and weren't wet yet when I took the car to the service center.

I discovered the whine about a week after I got the a/c and carpet fixed. It was not there before, I'm positive of it. I first thought it was the new cds, something wrong with the way I'd ripped tracks to MP3 etc etc, after which I finally concluded it had to be because the service guys screwed-up and got the wires and connections wet somehow before they fixed the A/c problem.

I was wondering what to do about it when I had to replace my Exide (went dead just like that. I hadn't used the car for 3-4 days, and one fine morning nothing worked). I switched to an Amaron (high-capacity model), and the same day I noticed that there was no more whine. I listened hard for the next few days, and it had indeed disappeared for all time. I had changed nothing - wires, connectors, amps - nothing in between discovering the whine and changing the batteries. The same CDs (that I thought had caused the whine) played well (without a whine) after the battery change. The whine MUST have had something to do with the batteries.

[Sam Kapasi]

The service battery provided, was serviced and the distilled water wasa OK. From hydrahoks experience I am beginning to think exide batteries may have a different resistance from others and may be more conducive to whine.

Guys lets keep our eyes and ears open shall we?

[Harrie]

Originally Posted by Sideways

And if all else fails theres always Aliminium Kitchen Foil - Thanks you Navin (Take A bow please Sir).

What do you do with aluminium foil? Wrap the RCAs with it? I am going nuts with this whine. It goes up and comes down all by itself.

@ Sam - You just made me realise this. The whine in my palio has gone down after the recent battery change. Both batteries were Aamaron. But this time the whine is down.

[Sam Kapasi]

HI Harrie,

I would recommend you first change your RCAs to good quality ones, what are you using right now?

[viper]

Originally Posted by Rudra Sen

But Navin, alternator whine was there..may be very little....

How to eleminate that totally? Because I also have it..

Hey Rudy,

Say tata to your bank balance.

Viper