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Old 28th April 2008, 18:36   #106
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Welcome to Headers on Team-BHP
Its strange..you welcome me after being on the forum for 1.5 years and creating a racket.
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Old 28th April 2008, 19:08   #107
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I seem to have wriggled out of the problem. I did try grounding the HU as @gunbir had confirmed. That did not work.
I had my speakers wired in parallel. Left front and rear to one channel of the 75.4, right front and rear to another channel. Disconnected the rear speakers. Voila!
So now I'm running only the fronts and sub. Rears disconnected.
Spoke to soon. The whine is back. Although above 3K rpm. So it's not perceptible in city driving. Sigh.

Will update after I rewire.
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Old 28th April 2008, 22:11   #108
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Shuvc, do you really think disconnecting the speakers is a solution??
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Old 28th April 2008, 23:11   #109
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was having a problem with whine in rear speakers as well .. even connecting rca wires directly from head unit to the amp without touching it caused it and disconnecting them stopped the whine. only solution was to reduce the gain/level for rear speakers on amp and it seems to work. set it to about 40% now. installer said that alternator is leaking current and there is a mild voltage all over the car body (metal) and to ask TASC to clear the grounding/fix it. need to check with them in the next service
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Old 28th April 2008, 23:23   #110
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Nope. Don't think it's a solution. Since I will be wiring the rears again. But I've been trying all sorts of things. Nothing has worked on a consistent basis.

A few more todos.
- amp power wire is very close to speaker wires near the amp. Will try to put some distance between them.
- will try reducing the gain on the amp
- might replace RCAs.
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Old 29th April 2008, 08:17   #111
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shuv, my suggestion would be to prioritize it this way:
1. Try reducing the gains
2. Check the RCAs

But I did not understand what you meant in your first point! Maybe a picture would help.

Last edited by rocksterraghu : 29th April 2008 at 08:18.
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Old 29th April 2008, 10:31   #112
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there is one method which my installer told me. he said that i put a capacitor over the alternator and ground it. he said go to any car mechanic and ask him to do. however no one on the forum confirmed this. i had asked couple of times. can someone verify this?
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Old 29th April 2008, 13:26   #113
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Quote:
Originally Posted by bottle View Post
was having a problem with whine in rear speakers as well ..
Quote:
Originally Posted by shuvc View Post
Nope. Don't think it's a solution. Since I will be wiring the rears again. .
are you guys only having a problem with whine when the rear speakers are connected?

a few simple checks.
1. power wire should not run parallel to RCA wire. Power wire can cross RCA wire at 90 deg but it should not run parallel.

2. Use good RCA wire. I have heard of too many problems with brands like BOSS. Avoid them. It is just not worth the trouble. Stick to well known International barnds like Monster, etc..

3. For the RCA wire make sure it does not have too many sharp bends. these bends can casue small ractures in the shield or wire and then the problems start. This is especially true where the RCA is connected to the amp. Also make sur that the RCA wire is not stressed. It should be resonably tight but there should be some play. A wire that is too taut can snap.
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Old 30th April 2008, 10:01   #114
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navin,

the powerwires are on the left side of the car while rcas are running in the middle of the car between the seats under the carpet

while testing the amp was on back seat and we pulled out HU and ran the rca over the seats so that it would not be influenced by anything. was still getting whine

currently using audison wiring from gunbir and also tried soundstram rca wiring. no difference

the installer said alternator was leaking current since whenever he touched the rca to the metal it would give a screech

Last edited by bottle : 30th April 2008 at 10:03.
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Old 30th April 2008, 10:49   #115
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Quote:
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the installer said alternator was leaking current since whenever he touched the rca to the metal it would give a screech

which car is this?

can you source another alternator just to check. I have not seen a bad alternator since the late 80s. I figured they had the process down to a science.
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Old 30th April 2008, 12:06   #116
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Originally Posted by navin View Post

which car is this?

can you source another alternator just to check. I have not seen a bad alternator since the late 80s. I figured they had the process down to a science.
Its a Palio Stile 1.6
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Old 30th April 2008, 13:34   #117
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... the installer said alternator was leaking current since whenever he touched the rca to the metal it would give a screech
IMHO it looks like the installer is pulling a fast one, and he has no clue of good grounding!

The alternator is what it is - if it is really leaking, it will only be dissipating some of the converted energy in self-heating, leading to insulation failure some day. But that is not the problem at hand. There is always some ripple present in the rectified DC, which is filtered to some extent by the battery.

If the ground connection of the HU and/or the amp is not proper, this ripple appears in the output, since the voltage on the main battery rail is w.r.t. ground. If one can check with an osci, one can see the ripple on the Pow Sup -ive pin of the HU / amp W.R.T. battery -ive and also HU / amp BAT input (Ground Loop). With a good DMM, you could also measure the voltage diff. between HU/amp PS -ive pin and the Battery -ive (or alternator DC output -ive).

Please check ALL ground connections for corrosion - don't pass over any of those assuming that it looks OK. Redo the amp ground connection. Also check how much (DC) voltage is there between outer ring of the RCA connector and the nearest ground.

As far as the RCA "screech" is concerned, even you can make it produce peculiar sounds by catching the connector so that you are touching the signal and ground together (works even better if you lick your fingertip before that). This is the standard way of checking signal cables in PA systems. It only proves that the amp is working, since it is amplifying all noise presented directly at its input!!!
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Old 30th April 2008, 17:33   #118
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Quote:
Originally Posted by navin View Post

which car is this?

can you source another alternator just to check. I have not seen a bad alternator since the late 80s. I figured they had the process down to a science.
Hope its not an alternator fault but will get it checked. Got a new alternator a couple of months ago only after the original one failed :( car is not yet a year old


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Its a Palio Stile 1.6
Yup, Thanks


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Originally Posted by DerAlte View Post

Please check ALL ground connections for corrosion - don't pass over any of those assuming that it looks OK. Redo the amp ground connection. Also check how much (DC) voltage is there between outer ring of the RCA connector and the nearest ground.

As far as the RCA "screech" is concerned, even you can make it produce peculiar sounds by catching the connector so that you are touching the signal and ground together (works even better if you lick your fingertip before that). This is the standard way of checking signal cables in PA systems. It only proves that the amp is working, since it is amplifying all noise presented directly at its input!!!
will get it checked out. could be the installer is mistaken but i dont think so. he did check grounding points for corrosion and scraped the metal around the grounding for the car battery even just in case. didnt work.

regarding the screeching sound i have no idea what it was about but they were going around touching the connectors to different parts of the car body

Last edited by bottle : 30th April 2008 at 17:35.
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Old 2nd May 2008, 20:12   #119
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Bottle..any updates on your ICE and its sounds?
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Old 2nd May 2008, 21:27   #120
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No sir havent gotten around to it yet. as of now reducing the gain/level for rear speakers to 40% has eliminated the whining sound. previously when it was at 50% it was faintly audible and at 60% volume on amp it was annoying. so driving around with this fix.

i usually listen to music front biased , faded to front by 2 so reducing rear levels gives me similar type of sound.
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