never knows best Posted July 29, 2014 Report Share Posted July 29, 2014 Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, Ive found that in systems that have noise problems, a ground loop is the culprit nine times out of ten. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifiers circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp. Dont connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit. Link to comment Share on other sites More sharing options...
Hugh G. Rection Posted July 29, 2014 Report Share Posted July 29, 2014 try using a piece of speaker wire to connect the negative side of your RCAs to the chassis of the head unit. should fix the problem. Owner of BigAss Ports Link to comment Share on other sites More sharing options...
BerT6801 Posted July 29, 2014 Author Report Share Posted July 29, 2014 Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, Ive found that in systems that have noise problems, a ground loop is the culprit nine times out of ten. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifiers circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp. Dont connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit. Ok....I should have been more specific on this one.. All the amps have seperate grounds leading to the same seatbelt bolt. I will try splitting them but they are less than 2' long. Only thing on another ground is the head unit, I have it grounded direct to the body of the vehicle behind the head unit. I may try to make a video of all this. try using a piece of speaker wire to connect the negative side of your RCAs to the chassis of the head unit. should fix the problem. I have tried this as well... no change... you can read a direct connection from rca negative to the body of the head unit with a volt/ohm meter Link to comment Share on other sites More sharing options...
slowfkncar Posted July 29, 2014 Report Share Posted July 29, 2014 hav you tried bypassing the kicker kx3?Yes I did.... the volume of the noise goes down a bit...but still very present Further testing tonight... I hooked up a external 12v power supply to the head unit alone....all noise is gone. So where does that leave me.... this screams noise in power at the head unit.... however I also ran jumper cables straight to battery and head unit....still noise... still full volume. So anytime you hook up the vehicles ground to a head unit in any way ( I have tried two head units) the noise is present. Even without 12v+, noise is still present the ground to your 4 channel amp, check it,make sure its tight with no corrosions. Usually, if your amp is making noise with or without the engine running indicates a bad amplifier ground. If the amplifier ground has a continuity of .005 (bad or loose) then it will try to correct it throug the next ground source, which will be the RCA's and those should not have any kind of high current. Also, how is your amplifiers on with the stereo disconnected? Also, Dont rule out the RCA's. If your using your iPod or phone to play music of course its not going to make noise because the noise floor is powered by a different source. The same reason why your stereo won't make noise on an external power source. But if you have a pinched RCA, anything you connect to the cars power/ground source will make noise. Please do not overlook this, you already made good examples of what could be wrong. Link to comment Share on other sites More sharing options...
Jessica Posted July 29, 2014 Report Share Posted July 29, 2014 You said you used another head unit but did you try different rca cables? Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
BerT6801 Posted July 29, 2014 Author Report Share Posted July 29, 2014 You said you used another head unit but did you try different rca cables? I guess I once again failed to mention this.... I have tried so much. I have tried different RCA cables... ran from the radio to the crossover and direct to the amp. Same issue. I can bypass the crossover all together and I admit the noise is not quite as loud...but it is still very present, I will do a reading on the ground wire and report back. Both good points. I was blaming RCA cables picking up something at first stab.... but I ran a brand new set from radio to crossover and nothing changed at all. Link to comment Share on other sites More sharing options...
Jessica Posted July 29, 2014 Report Share Posted July 29, 2014 hav you tried bypassing the kicker kx3? Yes I did.... the volume of the noise goes down a bit...but still very present Further testing tonight... I hooked up a external 12v power supply to the head unit alone....all noise is gone. So where does that leave me.... this screams noise in power at the head unit.... however I also ran jumper cables straight to battery and head unit....still noise... still full volume. So anytime you hook up the vehicles ground to a head unit in any way ( I have tried two head units) the noise is present. Even without 12v+, noise is still present I didnt see this post, i think you may need to try an torroid choke on the power or ground wire, they look like the pic below. I don't know where to get them though. Some members here use them with success, hopefully they can chime in. edit, you would just pass your wire through the hole. No soldering or anything. Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
SIDE SHOW Posted July 30, 2014 Report Share Posted July 30, 2014 check connections on the kx3 crossover, if you can notice a difference when you bypass that then more than likely it's playing a major role in your issue Link to comment Share on other sites More sharing options...
BerT6801 Posted July 30, 2014 Author Report Share Posted July 30, 2014 i have posted a video however its taking forever to upload....when its done here it is. Link to comment Share on other sites More sharing options...
slowfkncar Posted July 30, 2014 Report Share Posted July 30, 2014 So, with just your stereo and amp,powered from the car battery while the car isn't running (key in ACC/IGN) makes noise right. Have you tried connecting the deck and amp to the battery positive and see if the noise is gone with the key off? If it is not gone, and you have perfect grounds like you say,and the deck is good like you say, then I'm willing to be the amplifier is bad. If the problem is gone then the issue is with your vehicles electrical system. Could be something simple like a bad PCM ground or could be something fucked up like the alternator bridge rectifier on its way out. Let me ask you this, when the vehicle is running do you still have a buzz? Or is it now alternator whine? Link to comment Share on other sites More sharing options...
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