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azaudio
21-04-2004, 06:12 AM
Ok firstly the problem is not supression or coming from the motor.

I have a Kenwood f/l with changer under passenger seat , I have just installed a 1200w amp and 15 inch sub.
My RCA cables run on the same side of the car as my changer

Problem 1:
When listening to radio I get a constant wining sound from exsisting speakers and when I disconnect RCA cables from h/u it goes away,problem solved u say noooooo I ran a set of RCA cables over seats to amp incase it was picking up interference and same noise sooo ...?

Problem 2:
When operating cd in h/u or changer I can hear every motor movement in the mechanism and the noise comes from all the speakers not just the sub

Is my amp F_ _ ked or what its hardly used basically brand new is it causing a feedback and will a ground loop isolator on the RCA leads make a difference ??

HELP

twilightprotege
21-04-2004, 06:17 AM
you need to have the rca's as far away from any electrical wiring as possible, preferably on opposite sides of the car.

also, it sounds like your alternator is the problem to me (i'm not the most knowledgeable on car audio though)

JynX
21-04-2004, 06:22 AM
where did you ground the amp too?

azaudio
21-04-2004, 06:52 AM
Amp is mounted on back of seat and grounded onto the bolt that mounts the seat to the body less than 30cm in length and same diameter as power cable.

It cant be the RCA location as I ran another lead over the seats a far way from the vehicle wiring and there was no change.

The noise is not the alternator type and happens even with the vehicle switched off.

Could it be coming through my power cable ?? hmmm will check

twilightprotege
21-04-2004, 07:29 AM
try better rca leads too.

i'd be pretty sure if it happens when the power is off, the noise is coming from a power cable

from the hu to the amp, what is the closest the rca's get to the power cable?

JynX
21-04-2004, 07:47 AM
I would be inclined to try another ground spot.

Cosmo Dude
21-04-2004, 08:51 AM
Or
1. Leave the existing ground points and install another ground between the ground connector on the H/U and the AMP.
2. Temporarily connect the AMP as physicly close to the H/U with very short RCA leads. If the AMP works well then it's your leads, if not it may be a ground hum in the AMP.
3. If that doesn't work leave the new ground in place and return the AMP to its normal spot, make new RCA leads but only connect the shield to the plugs on the H/U end. The shield should be ground and any noise induced into it won't then be transfered into the AMP

azaudio
21-04-2004, 11:49 AM
The power cable does come pretty close .

Will try ow wise sound guru people :D

thx

azaudio
21-04-2004, 11:54 AM
Any Idea what woild cause a ground humm inj the amp by the way ?

Would it be a dry spot in the amp,loose pc board , capacitor ?

thx

twilightprotege
21-04-2004, 11:58 AM
the closest a rca lead should come to the power lead is at the amp. they should be atleast 50cm appart the rest of the way, the further the better

Zed
21-04-2004, 12:30 PM
What amp do you have if you don't mind me asking? Some amps themselves are prone to introducing noise, so its not necessarily due to bad wiring.

Having said that, definitely check out your grounding points. If you haven't already, ensure you sand all the paint off where the seat mounting bolt is - you want good metal contact.

And for noise rejection, unshielded twisted pair RCAs are better than shielded RCAs so it may be worthwhile trying to find a pair of those and plug them in and see if it makes any difference.

I'll try and a find a noise elimination tutorial online for you. Muting plugs are also a good way of finding out where exactly the noise is being introduced into your system.

mutek
21-04-2004, 01:26 PM
haha i had my RCA's right next to my power cable in my first install -- sounded like a had a turbo in my old 84 Corona Wagon :D

geetee
22-04-2004, 04:55 AM
why not try connecting your ground cable directly to the battery? i`m no expert but surely this would eliminate interference from other sources.
remember your fuel pump will be in the back seat area. maybe this is a bit close for comfort. :?

azaudio
22-04-2004, 05:24 AM
Ok did all the above , had three earthing points at the end of the day , changed rca`s , changed all cable runs to outside vehicle and guess what .... NO FLIPPIN DIFFERENCE :lol: .

I think its the amp so Im takin it out and checking it on the bench for dry spots etc , will keep you informed

Its a 2 channel Star Sound 1200w with xover , Ive installed a few of these into other vehicles and no problem , I think I have a dud

Thx all

Dogo
22-04-2004, 08:05 AM
wouldnt it be quicker to just plug a different amp in, than open the one u have and thus void the warranty ?

azaudio
22-04-2004, 08:26 AM
Well Dogo that would be much easier but the catch is I dont have a warrantee on the amp I got it for nothing so I dont mind spending some time on it .(nice to have friends in high places) but I am going to try another amp I have lying around.

Zed
22-04-2004, 09:20 AM
Before you do that, try making some muting plugs and plugging them into the inputs of your amp. If the interference noise is still present then the noise is coming from the amp.

Muting plugs are basically RCA plugs that you have shorted out - ie connected the inner plug to the outer shield with a loop of wire.

And I can't say I've ever heard of the brand Star Sound - but almost any amp that is marketed as 1200W (peak/max I presume) I'd be a little dubious about its actual performance.

azaudio
23-04-2004, 05:37 AM
Hey Dogo no use running down our local brands - very uncool

Check out http://www.starsound.co.za and as for performance its pretty good stuff not like other brands where u pay for a brand name and the product is really crapy. ..|..

Anyways thx will give the plugs a bash :)

azaudio
22-05-2004, 12:32 AM
Well opened up amp myself and went over all solder points in case of a dry joint , rerouted all cables including shuttle cable and amplifier cables , switched on and taadaa the ****y noise is gone so one of the above or all of the above worked , :lol: now I am happily booming away with my 15in again

Thx all for the help

platypus
23-05-2004, 12:55 AM
i was just about to ask if the radio is ok too!!!