strange alternator whine issue

rijndael · 07-16-2008, 08:47 PM

ok...strange problem.

I already know the solution to my problem to be to just use the old wires from the sound card to the amp...or i can get one of those things from best buy or circuit city.

the problem is that i had this really old set of crappy RCA wires going from my sound card to my amp, and one of the connections was cutting out all of the midrange frequencies on my right channel. so naturally, i replaced them. I went out today and bought some monster cable, and i now have my speakers working. the only problem is that now, i have this horrible alternator whine which i did not have before. the sound quality is the same as it was before, except now i have all of my speakers producing sound instead of just the remaining 2 other speakers on the passenger side.

has anyone ever had this problem, and how am i hearing the alternator whine now, when i wasnt before with my old cable? even before the line shorted out, i never had the whine before.

any guesses or solutions?

Thanks for any help you can give. and sorry if this seemes a little jumbled, im really tired right now.

lbridges · 07-16-2008, 09:52 PM

Worth a read for a possible cause: http://www.diysubwoofers.org/project...f/alternat.htm

warnockm · 07-16-2008, 10:30 PM

I have a similar problem. It started a while after my stereo/amp was installed. I think my problem is a cap or something blown in the amp.

Another weird problem is a get a louder whine when i run it off the battery. How's that possible? haha

Tidder · 07-16-2008, 10:47 PM

Typically it's a ground loop or a floating ground. Are the cables longer or shorter than the old ones you had in there? That definitely makes a difference. All kinds of things come into play that would introduce a ground loop and engine/alternator noise. Gauge of wire, quality of cable, length of cable, interference, etc. Generally the way I've fixed in both of my installs, since they both had the problem, was to ground my audio output's ground (output from PC) to the ground of my car. Same with inverter installs, grounding the PC's power supply ground to the car ground/body took out my whine when I had the inverter.

rijndael · 07-17-2008, 08:30 PM

the quality of the new cable is definitely better, as well as longer. My computers power supply is grounded already, has been from the beginning.

the old cable was a regular headphone jack connector y-adapter

[/media] now i have this:

with these cables:
http://www.abt.com/product/21180.html the only difference is that mine have gold connectors

and i read the writeup that ibridges mentioned...good read...ill check to see if that is my problem...and a sniffer seems pretty cool. the only thing i dont get is what he means with this statement "I realized then that if I used a single shielded cable, with 2 "hot" conductors, to carry both channels, then the loop area of both channels would be small. Voila, no more noise, even with the active xover reconnected."

the way i imagine it, i changed to the single cable with 2 connectors..but thats what allows me to hear the noise...

ohh well...i just need to see if i can find out where that noise is originating from.

Thanks guys..ill keep you all posted...and any more ideas are welcome as well