C70_london Posted August 10, 2004 Report Share Posted August 10, 2004 Hi Folks - I've got some problems with whining noises coming through the speakers...and need some help ! I haven't a clue about this kind of stuff. The car is a '98 C70 with the SC-901 premium sound system.There's a couple of components to the noise...1) There's a faint, high pitched whining noise that comes through all speakers, as far as I can tell. With the stereo turned on, but the volume down as low as it can go, it's faint...as soon as the volume goes up one 'click' on the dial, it gets a little louder and stays at that level regardless of volume. The pitch of this whine is related to engine speed (from the alternator ?) If I turn on the side/headlights, it gets louder again....and at the same time, component number 2 strikes up 2) Having the headlights on brings in what seems to be a constant pitched noise. If I use the dashlight dimmer, the noise gets a good bit louder and it doesn't seem to matter how much the dimmer is turned.I guess something needs earthing and/or shielding (that's my knowledge exhausted now )...but where should I head first ???Any help would be MUCH appreciated Thanks...Richard Link to comment Share on other sites More sharing options...
Bing_0 Posted August 10, 2004 Report Share Posted August 10, 2004 do you have an aftermarket amp installed? or is it a stock system? if its an aftermakret system, do a search for alternator noise in this forum and you will see some good answers.b Link to comment Share on other sites More sharing options...
Guest Guest Posted August 10, 2004 Report Share Posted August 10, 2004 do you have an aftermarket amp installed? or is it a stock system? if its an aftermakret system, do a search for alternator noise in this forum and you will see some good answers.b←Nope...it's all stock. I had the same problem with the SC-900 before I swapped it out for the 901. Assuming it's the alternator, is there some noise reducing component that could have failed or is it more likely to be that the alternator is now producing noise that it didn't before ??I'll take a look through the archives for 'alternator'...I had a quick check earlier on 'whine' !Thanks.... Link to comment Share on other sites More sharing options...
BenW Posted August 10, 2004 Report Share Posted August 10, 2004 You have a bad ground somewhere with the head unit or the amp. i cant explain how to fix it but that is what you got. Link to comment Share on other sites More sharing options...
styx0r Posted August 18, 2004 Report Share Posted August 18, 2004 You have a bad ground somewhere with the head unit or the amp. i cant explain how to fix it but that is what you got.←I agree. This sounds like a grounding issue to me. You could replace the stock grounding wires in the engine bay (There was a pictoral example of how to do so around here...) and run a better ground from the headunit, rather then tapping into the ground provided on the wiring harness - Run the ground wire from the head unit down to the chassis. Make sure to remove paint before terminating the connection on the metal.-edit: anything that's poorly grounded will introduce electronic "noise" into the system. Your speakers are picking up that noise thru the +12 and ground connections on your head unit. Stop the noise before it gets to the headunit. Re-ground your motor (which may help performance, anyway).... Link to comment Share on other sites More sharing options...
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