Have you tried running a new set of RCA cables? Even a cheap set on top of the carpet to help narrow down further. I have personally seen cables that had screws driven through them or were pinched in a spring clip on a body/trim panel, or it is even possible to get a set of cables with flaws from the factory.
If the noise is still there, then I would investigate the HU. I think you said it was a pioneer-- I don't have a lot of experience with their heads, but if I recall there is a fusible link or fusible resistor on the RCA shields inside a pioneer head. It will open if there was/is ever even a brief fault that causes the shield to act like primary ground. If a new set of cables doesn't remedy it, then you can try grounding the shield at the source unit, I would personally use a very low current fuse in line with this ground just in case there is still a problem. I would guess probably 2.5a or less... If the noise goes away when you ground the shield at the source, then you head unit needs serviced.
*Edit* Maybe I am misunderstanding, but it seems you also gave us some conflicting information. In the first post you said you removed the RCA cables from the amp and with no input there was still noise. You go on to tell us in you more recent post that the noise is gone with no input to the amp. Did something change, or am I just misreading this? I think that my advice above is still valid, but you really need to take a very systematic approach to isolate the issue. Maybe even take notes of exact steps as you go and only do one thing at a time. It seems that you are making a good attempt at ruling everything out, but it's easy to get ahead of one's self and come to conclusions that are not valid.
Good Luck,
Jason
If the noise is still there, then I would investigate the HU. I think you said it was a pioneer-- I don't have a lot of experience with their heads, but if I recall there is a fusible link or fusible resistor on the RCA shields inside a pioneer head. It will open if there was/is ever even a brief fault that causes the shield to act like primary ground. If a new set of cables doesn't remedy it, then you can try grounding the shield at the source unit, I would personally use a very low current fuse in line with this ground just in case there is still a problem. I would guess probably 2.5a or less... If the noise goes away when you ground the shield at the source, then you head unit needs serviced.
*Edit* Maybe I am misunderstanding, but it seems you also gave us some conflicting information. In the first post you said you removed the RCA cables from the amp and with no input there was still noise. You go on to tell us in you more recent post that the noise is gone with no input to the amp. Did something change, or am I just misreading this? I think that my advice above is still valid, but you really need to take a very systematic approach to isolate the issue. Maybe even take notes of exact steps as you go and only do one thing at a time. It seems that you are making a good attempt at ruling everything out, but it's easy to get ahead of one's self and come to conclusions that are not valid.
Good Luck,
Jason
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Sorry, I really wasn't very clear regarding the battery thing.
My car has actually developed a bit of a whine in the past year, and as you have shown with yours, it is the alternator/amp that are producing it.
Hard to blame the rca cables when they are not connected!
I have a slowly dying battery, and have noticed that the whine is worse right after starting from cold when the alternator is under load. This is again worse after I have been sitting in the car listening to music under battery power.
My garage charger indicates that the battery isn't achieving a full charge and this tells me that there is an issue.
Is hard to justify a new battery to satisfy audio perfection, at least for me it is, although the whine is a disappointment.
I did put a 5uf 275v polypropylene box capacitor on the + lug of the alternator, which seemed to help slightly, and improved the overall sound as an unexpected bonus. I may try a snubber type of circuit on the alternator also before a new battery, unless it dies first.
My car has actually developed a bit of a whine in the past year, and as you have shown with yours, it is the alternator/amp that are producing it.
Hard to blame the rca cables when they are not connected!
I have a slowly dying battery, and have noticed that the whine is worse right after starting from cold when the alternator is under load. This is again worse after I have been sitting in the car listening to music under battery power.
My garage charger indicates that the battery isn't achieving a full charge and this tells me that there is an issue.
Is hard to justify a new battery to satisfy audio perfection, at least for me it is, although the whine is a disappointment.
I did put a 5uf 275v polypropylene box capacitor on the + lug of the alternator, which seemed to help slightly, and improved the overall sound as an unexpected bonus. I may try a snubber type of circuit on the alternator also before a new battery, unless it dies first.
If the battery is starting to fail this could well be your issue, I would suggest visiting a mechanic to have the battery tested, as if it has a shorted cell it could damage the alternator which is much more to replace than a battery.
You could prove this for yourself by substituting a known good battery and seeing if the noise goes away.
You could prove this for yourself by substituting a known good battery and seeing if the noise goes away.
Yes all speakers wires are good. The only side that maybe shorting is inside a speaker itself and I highly doubt that.
Yea I understand setting my gain into normal levels. But even in normal level I can't hear a thing! I am used to loud music and I wanna up the gain a little bit higher. I am still way way far from max. It annoys me that I have to set my gains lower just to not hear noise. I want solve my actual problem.
That's a very expensive solution and unlikely to work. Amplifiers are made to work well with noisy power supplies.
When you tried the tweeter, did you have ALL speaker wires disconnected from the amp?
Have you tried measuring the AC (not DC) voltage on the B+/ground terminals of the battery and the amp?
Have you tried comparing the AC from one jeep to the other?
Do you have a spare 6x9 or similar coaxial type speaker and a crossover capacitor of about 47uf?
When you tried the tweeter, did you have ALL speaker wires disconnected from the amp?
Have you tried measuring the AC (not DC) voltage on the B+/ground terminals of the battery and the amp?
Have you tried comparing the AC from one jeep to the other?
Do you have a spare 6x9 or similar coaxial type speaker and a crossover capacitor of about 47uf?
Sounds like the passive crossovers are too close to a 12v wire that is generating emf and it's making it to the speaker. A fuel pump wire being close to the wires running to the crossover or after it can do it, so can dimmer/lighting wires that have switching regulators and even pwm blower motor controller wiring can do it.
I've had it happen on my own install and had to diagnose it on customers' vehicles a few times over the years as an installer. Some crossovers are sensitive to it depending on how the internal components are arranged and proximity and frequency of the emf source.
I've had it happen on my own install and had to diagnose it on customers' vehicles a few times over the years as an installer. Some crossovers are sensitive to it depending on how the internal components are arranged and proximity and frequency of the emf source.
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Out of curiosity, why do you seem so intent to just slap a band-aid on this? There is a problem somewhere and you have come to a forum that predominately discusses repair of car audio problems.
To put it gently, it is counter to most of our natures to just fix symptoms or cover up the problem with a band-aid. I personally love the "hunt" and puzzle nature of car audio repair. I'm sure many of these fine other folks here feel similarly. You have some of the smartest people (not myself!) I have ever encountered here and they are trying to help you but you don't seem to be interested in listening.
As Perry said, most car audio amplifiers are designed to work in a noisy environment. There is no reason that you cannot track this down and find the issue. There is no magic involved here. You have your other jeep as proof that you can have a virtually noise free installation.
Good luck, I truly hope you find a solution that it adequate for yourself.
Later,
Jason
To put it gently, it is counter to most of our natures to just fix symptoms or cover up the problem with a band-aid. I personally love the "hunt" and puzzle nature of car audio repair. I'm sure many of these fine other folks here feel similarly. You have some of the smartest people (not myself!) I have ever encountered here and they are trying to help you but you don't seem to be interested in listening.
As Perry said, most car audio amplifiers are designed to work in a noisy environment. There is no reason that you cannot track this down and find the issue. There is no magic involved here. You have your other jeep as proof that you can have a virtually noise free installation.
Good luck, I truly hope you find a solution that it adequate for yourself.
Later,
Jason
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I have to disagree with you on me not being interested. I've listened to every post here and I've went to apply every recommendation to my actual situation. I've said in the beginning of the thread that I do NOT want to put a band-aid over my problem after someone recommend me to just put a power filter. I do not want to solve it with a filter and I am still convinced that I cant tackle it. Like you said it's an interesting hunt.
Sorry If I seem a bit "rushy" and impatient. but I've been dealing with this jeep for the past 6 months and grown tired a bit. Excuse me if I offended anyone here.
Thank you so much for the help guys and I deeply appreciate all the help and advice I can get. I don't show that in text because how frustrated I am in solving this issue. Thanks again.
I will take the advice on the last couple of posts and see how it goes.
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Yes I have done that. As soon a single RCA touches the amp input noise starts coming with nothing on the amp except the test tweeter
Hmm before I do that. What do I get if i see some AC voltage. I am trying to understand the process here a bit. Sorry bear with me perry xD
I know that alternators convert AC into DC. BUT some residual AC voltage is transmitted into my system then amplified by my AMP. Causing the noise. If I see AC voltage, what can I do about this small AC voltage? How do I get rid of it? Is there anything I can do to stop my alternator from producing some AC and make it produce pure DC?
For the spare 6x9 coaxial speaker, Yes I do have a spare one. Though "crossover capacitor" sorry I am not familiar with a "crossover" one. What's the difference between that and a normal capacitor?
Thanks for all the help perry! You seemed that you tackled this problem like 70 times before!
The jeep tweeters are above the dash. So there is literally no way you can wire them unless you go through the dash! You maybe right on this one BUT let me ask you one question If you don't mind.
I've run the system just now with the amp off but everything else is on, and there was no noise. If I am receiving noise from lets say a fuel pump wire for example. Should I hear noise even when my amp is off? If I don't hear noise, then I can assume that all my wiring into in my dash is ok? Assuming that my speakers are powered of course. So a test I can do is to determine if my wires in my dash or the crossovers are picking up noise is to disconnect the speaker wires from the amp and power them alone. If I still hear noise then It's somewhere in my dash that I am picking up my noise.
If I don't hear any noise and I can play music without any interference, then It is NOT the crossovers or speakers in my dash? But the noise is being picked up from the amp side.
Because I've done a similar test by putting a new speaker wire with a mock tweeter without using the actual wiring and I still hear noise. Thats why I said its coming from the amp
I think I can answer a few of your questions above, at least in part. Most alternators generate 3 phase AC and use a 3 phase bridge rectifier to produce DC. Rectified AC will always have some AC ripple in the DC, but rectified 3 phase AC will have far less ripple than something like the rectified mains in your house. A failing diode in the alternator could allow a lot of AC through though and could be the source of your issue. You mentioned that you swapped the alternator though so that would seem to rule that out.
A crossover capacitor is typically a unpolarized electrolytic cap. Your average run of the mill electrolytic cap will be polarized and will not work. You used to be able to get these at Radio Shack, you may still be able to if you have a Radio Shack around. I know you can easily order them on line, Parts Express has a pretty good lineup to look through.
Question, when you swapped the amp from the other Jeep, first was it the same exact model, and second, did you bolt it down and have it installed exactly like the one that is installed and having issues?
I completely understand being frustrated, but you will get it. Hang in there!
Good luck,
Jason
A crossover capacitor is typically a unpolarized electrolytic cap. Your average run of the mill electrolytic cap will be polarized and will not work. You used to be able to get these at Radio Shack, you may still be able to if you have a Radio Shack around. I know you can easily order them on line, Parts Express has a pretty good lineup to look through.
Question, when you swapped the amp from the other Jeep, first was it the same exact model, and second, did you bolt it down and have it installed exactly like the one that is installed and having issues?
I completely understand being frustrated, but you will get it. Hang in there!
Good luck,
Jason
In general ,
In some vehicles noise is an issue with any configuration with any equipment you install. Of the thousands of installs I have done the best solutions/steps to take are these. 1st, If the noise is incredibly bad, then there is probably an open trace in your head unit on the RCA ground. Connect RCA ground to ground on radio. If it quietens down 80% repair your radio.
Most noise is created because there is a voltage potential between your head unit RCA ground and the ground of your amplifiers input circuitry. The best solution is to buy a line driver with a built in power supply. This power supply creates its own ground that will be defined by the input of your amp. This is a 95% fix.
Other solutions include a inline RCA noise filter(inline transformer). Losses are usual however. A power coil for your amps power line. Limits power to your amp.
Other issues I have encountered are fuel pumps and headlights. Do not ground amps close to lighting, need a couple of foot. Fuel pumps create a strong magnetic field and draw that will cause fluctuations in ground potential.
Waste of money are 80$ RCA cables. 99% of all cars that have noise problems still have noise problems with 80$ RCA cables.
Grounds can be an issue once in a while, but if your car's power ground is bad you will have other problems generally. Noise is caused by ground issues but it's the ground potential between your source and amplifier circuitry.
Final solution. Use the outputs of your radio and install a line output converter, Scoche makes one, Metra used to make one. The requirement is, it must have transformers to step down the voltage. I bought one from Walmart a while back, it had a gain control on it with a amp turn on. It worked great! If you use this your noise will probably be gone unless your amp is mounted over a fuel pump or connected to a lighting circuit. It would be unusual.
Brian
In some vehicles noise is an issue with any configuration with any equipment you install. Of the thousands of installs I have done the best solutions/steps to take are these. 1st, If the noise is incredibly bad, then there is probably an open trace in your head unit on the RCA ground. Connect RCA ground to ground on radio. If it quietens down 80% repair your radio.
Most noise is created because there is a voltage potential between your head unit RCA ground and the ground of your amplifiers input circuitry. The best solution is to buy a line driver with a built in power supply. This power supply creates its own ground that will be defined by the input of your amp. This is a 95% fix.
Other solutions include a inline RCA noise filter(inline transformer). Losses are usual however. A power coil for your amps power line. Limits power to your amp.
Other issues I have encountered are fuel pumps and headlights. Do not ground amps close to lighting, need a couple of foot. Fuel pumps create a strong magnetic field and draw that will cause fluctuations in ground potential.
Waste of money are 80$ RCA cables. 99% of all cars that have noise problems still have noise problems with 80$ RCA cables.
Grounds can be an issue once in a while, but if your car's power ground is bad you will have other problems generally. Noise is caused by ground issues but it's the ground potential between your source and amplifier circuitry.
Final solution. Use the outputs of your radio and install a line output converter, Scoche makes one, Metra used to make one. The requirement is, it must have transformers to step down the voltage. I bought one from Walmart a while back, it had a gain control on it with a amp turn on. It worked great! If you use this your noise will probably be gone unless your amp is mounted over a fuel pump or connected to a lighting circuit. It would be unusual.
Brian
You mentioned that the noise comes when the rca is touched to the amp, but I thought you had mentioned before that it would make the noise with the rca removed; I'm confused again.
Happens a lot to me, so maybe I missed something?
I also thought about my battery/load situation, and it really shouldn't be making noise ragardless of the load. I may be making a filter for my power input using a 1uh inductor and a 100uf capacitor since mine is power related.
Happens a lot to me, so maybe I missed something?
I also thought about my battery/load situation, and it really shouldn't be making noise ragardless of the load. I may be making a filter for my power input using a 1uh inductor and a 100uf capacitor since mine is power related.
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