Oreo931 Posted October 7, 2010 Report Share Posted October 7, 2010 I've been having problems with "alternator whine" noise ever since I installed my sub and amp. I am running an Alpine type E with an Alpine MRP-450 amp. I used a name brand wiring kit to install it (can't remember company, but it is reputable). I am using 2 gauge wiring for the power and ground wires. Here is the wire routing: Drivers side: -power wire from battery to amp -signal wire from headunit to amp (tells the amp when the radio is on) -ground wire from amp to a grounding point under the rear driver seat Passenger side: -RCA cables from headunit to amp Here's where it gets confusing... I am running the stock headunit (SC premium sound series w/ single cd) in addition to the OEM amp. I bought an amp adapter from a member on here that allows me to use my Alpine amp in addition to the OEM amp. It basically splits off the amp connection so I can connect my OEM amp, and also RCA cables. I also have a blitzsafe iPod adapter hooked into the CD changer port on the back of the headunit, but I don't think that has anything to do with this (the alternator whine was there before I installed this). I checked the amp ground under the rear drivers seat, it looked good but I sanded it with low grit sand paper just to make sure there was a good connection. I also adjusted with the gain on the amp to see if that would help, but it didn't. I've been reading about this issue and I think it's most likely caused by a ground loop, but since I'm running 2 amps and a bunch of factory equipment, I have no idea where to start looking, or even how to troubleshoot this. So I'd appreciate any help. Thanks! Link to comment Share on other sites More sharing options...
drin850 Posted October 7, 2010 Report Share Posted October 7, 2010 is it the original altenator? mine was whining for a while, then it started to smell. And whenever i would open 2 windows at the same time, all the lights would dim. Driving it home one day and all the lights on the dash came on and the alternator finaly died. Good thing i had an extra one at home. Link to comment Share on other sites More sharing options...
Oreo931 Posted October 7, 2010 Author Report Share Posted October 7, 2010 is it the original altenator? mine was whining for a while, then it started to smell. And whenever i would open 2 windows at the same time, all the lights would dim. Driving it home one day and all the lights on the dash came on and the alternator finaly died. Good thing i had an extra one at home. I replaced it a couple months ago with a rebuilt unit. The alternator isn't making noise, I'm getting an alternator whine noise through the speakers when the radio is on. The sound is RPM sensitive (gets higher pitched with higher RPMs) Link to comment Share on other sites More sharing options...
flyfishing3 Posted October 7, 2010 Report Share Posted October 7, 2010 (gets higher pitched with higher RPMs) IMO thats clearly a ground issue. get some of those belts that hang down. :P Link to comment Share on other sites More sharing options...
drin850 Posted October 7, 2010 Report Share Posted October 7, 2010 I replaced it a couple months ago with a rebuilt unit. The alternator isn't making noise, I'm getting an alternator whine noise through the speakers when the radio is on. The sound is RPM sensitive (gets higher pitched with higher RPMs) aahhh alright. i came across this article. maybe it wil help http://www.termpro.com/articles/noise.html Link to comment Share on other sites More sharing options...
crazykn Posted October 9, 2010 Report Share Posted October 9, 2010 You may have to resort to a ground loop isolator. Supposedly it does lower sound quality, but to my ear, I cannot preceive a real noticible difference. The ground loop isolator attenuates the very very high and very very low frequencies, but retains the normal listening frequencies. I've tried noise filter blocks, but they didn't solve the alternator whine, the ground loop isolator did. I was getting my whine, because I have a iPhone 4 hooked up to my Blitzsafe Aux in and the 12 volt USB power adapter was causing my ground loop. I installed the ground loop isolator between the iPhone and the Aux adapter and it has cured the alternator whine! From radioshack: http://www.radioshack.com/product/index.jsp?productId=2062214 You have to install this between the offending device and the rest of the system. Link to comment Share on other sites More sharing options...
yangotang Posted October 9, 2010 Report Share Posted October 9, 2010 I had a nasty alternator whine from my carPC's system. I removed it for about 1 week, then dropped it back in, and now it's gone. I'm guessing that there was a floating ground somewhere inside the car that caused it, and am going to resort to a ground loop isolator. Link to comment Share on other sites More sharing options...
Reximus Posted October 9, 2010 Report Share Posted October 9, 2010 if it's a ground loop problem, from the article that drin850 have provided, looks like you have to ground all your audio equipment at one ground point... hence grounding both amp and the factory head unit at one same point on the chassis. i guess this would mean you have to cut and rewire the oem head unit ground to splice them with the amp ground all together then cheers! Link to comment Share on other sites More sharing options...
Oreo931 Posted October 9, 2010 Author Report Share Posted October 9, 2010 You may have to resort to a ground loop isolator. Supposedly it does lower sound quality, but to my ear, I cannot preceive a real noticible difference. The ground loop isolator attenuates the very very high and very very low frequencies, but retains the normal listening frequencies. I've tried noise filter blocks, but they didn't solve the alternator whine, the ground loop isolator did. I was getting my whine, because I have a iPhone 4 hooked up to my Blitzsafe Aux in and the 12 volt USB power adapter was causing my ground loop. I installed the ground loop isolator between the iPhone and the Aux adapter and it has cured the alternator whine! From radioshack: http://www.radioshack.com/product/index.jsp?productId=2062214 You have to install this between the offending device and the rest of the system. Just purchased! Thanks :D Link to comment Share on other sites More sharing options...
blazen244 Posted November 17, 2010 Report Share Posted November 17, 2010 As mentioned the grounding potential between two units are different you can ground from the housing of the radio to the car just like the amp to see if this corrects the issue. Link to comment Share on other sites More sharing options...
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