99% of the time, ITS NOT CAUSED BY RUNNING POWER WIRE WITH THE RCA CABLES!!! Before you bring your car to the shop asking the tech to re-route the rca's or looking for a ground-loop isolator, consider this...

First of all, your whole chasis is being used as a conductor in a dc current application, so, basically, your RCA cables are almost always run next to a "power wire" no matter where they are in relation to your amps power wire. This is bc the negative terminal of your battery is contacted to the chasis for ground, thus completing all electrical circuits in your vehicle.

Alternator whine is usually caused by just a cpl scenarios, the first of which is a ground-loop. A ground-loop is caused by creating a difference in potential (a difference in potential just means that one grounding point has more resistance than the other grounding point) btwn two grounded loads. (just a bad ground). Most of our vehicles we have a unibody chasis. The manufacturer creates your chasis by using just a cpl spot welds, and some crazy adheisives. Well, the cars main ground is under the hood, within around a foot from the negative terminal of the battery. The underside of your rear deck lid is metal, sure, but prob isn't the best grounding point considering that there is prob just a few spot welds that connect it to your negative battery terminal, increasing resistance on that particular circuit. Also, try to avoid mounting your amp directly to metal in your vehicle. Remember that your whole chasis is a conductor? You may as well take 20' of your power wire and wrap it around your amp, I bet you'd get some electrical noise in that case also, huh? Also, make sure your radio is grounded properly. That is where the source is that is sending the audio to your amp in the first place. So, if there is a ground loop there, of course it's going to be transmitted through your RCA cables into your amp.

If fixing grounding issues doesn't solve your electrical noise, we need to consider your equipment. Cheap equipment is the main culprit... If you bought your "rockwood" (not Rockford) amp from the flea market for $20, I mean seriously, it cost you $20 bucks for a reason! And the sad part is, someone actually made a profit off of that piece of s**t... They are cheaply made, using the cheapest components, they say they have 8 billion watts of power, but have a 10 amp fuse on the side of it, give me a break! Don't bring that into my shop and ask me to fix your alternator whine when you have something like that in your car, I'll send you pounding pavement. You get what you pay for with car audio. Please consider that anytime you invest into your in car entertainment.

On occasion, however, I have seen very nice equipment fail. This is usually do to preamp Jack failing somehow. Usually the negative contact to the circuit board weakening or breaking somehow... But, since we bought product from a respected manufacturer from an authorized dealer, guess what!? WARRANTY!!! Hooray for that! Thank goodness we spent an extra cpl bucks!

At the end of the day, can we please get over this myth that running RCA cables next to your pwr wire causes your alternator whine? Sure, it's happened b4, with ppl using sh**ty RCA cables, but like I said, 99% of the time, this isn't the case now days

end rant.

 

rant = awesome!!!

 

Thx for agreeing Cobb, I'm sure u deal with this on occasion as well... I just wanted to add a cpl other points to this, based on what I've been seeing over the years...

If you do have alternator whine, sure, a ground loop isolator (AKA, "one of those noise filter thingies that you hook up to your amp") can help filter the noise somewhat, I don't remember who said it, it was s/o on Honda-tech, but they said it is only a band aid, you should really fix the actual problem... AMEN!!!

Also, you remember when I stated that a ground-loop is caused by a difference in potential? Well, if we have a larger sized power wire than the ground wire, we will also create a difference in potential (increased resistance btwn the (+) side of the battery vs. the (-) terminal. Please, s/o correct me if I'm wrong, but unlike an AC circuit in our homes which alternates polarity at 60 cycles per second, our DC circuits in our cars' (+) lead pushes electrons through the power wire, while the (-) terminal receives protons from the ground side to complete the circuit, (no alternating polarity on conductors). (I could be wrong on the terminology, I've Been drinking a lot of beer and watching Monday night football and it's been over ten yrs since I first studied this stuff ), but if we have excessive amounts of electrons (thicker power wire) with a smaller amount of protons (throught a smaller ground wire), there ends up being two concerns here... The main point being the difference in potential btwn the two conductors causing the ground loop (alternator whine), and a secondary concern being that the extra protons have to go somewhere... Where do they go!? I think it was kirchoff's law that stated that the sum of current entering a load (in this case, your amplifier), must equal the amount of current leaving the load. So if the conductor on the (-) side of the load is smaller wire, those extra protons on your power wire that can't all fit through you ground wire will turn into heat! Are you blowing fuses? Or melting fuse holders? Or is your amp over-heating and shutting down? Check your ground! I hope this info helps somebody out!

 

I think I might print this and hang it up.

 

What a coincidence! Look what I just pulled out of a 2007 charger today... A bestbuy in Columbia, South Carolina performed the original install. The customer complaint was that has subs were cutting in and out, then finally shut off for good... This was due to the fact that the battery was in the trunk, he had two amps and a cap that had in total, prob about 12' of ground wire, with only about 4' of power wire. The extra length of the ground wire caused excessive resistance in the circuit, scorching the wire, and melting the fuse holder. Thank goodness there was no fire!

 

DAMN. Just one of many reasons I don't let those hacks touch my s**t

 

I think the best part of the original post is the last section, "Sure it's happened before with people using SH*TTY rca cables."

My comment thingy is you will hardly ever hear this on a sub amp, because the lowpass will eliminate the whine, so no harm, AS LONG AS YOU USE A GOOD GROUND. rule of thumb on a 4ch i always run the the RCA and speaker wire together down the other side of the car because normally the wire bundle i run is the same size as 4 gauge wire, so i separate for room. rarely do i run into a problem where changing the side for the car fixes anything.

on ANOTHER note, is it just me, or isn't there a LONG TIME argument with the old school wiring guys that current flows neg ---> pos?? i know i'm not the only one that hears old timers talk about that.

YAY BEER!!!

 

on ANOTHER note, is it just me, or isn't there a LONG TIME argument with the old school wiring guys that current flows neg ---> pos?? i know i'm not the only one that hears old timers talk about that.

YAY BEER!!!


You're def not the only one! LOL! Im sure I'll hear plenty of debating from the old timer's on the running of RCA's with the power wire too, I only made this post bc of after years of trouble-shooting alternator whine, I've found that hardly ever does re-running RCA's fix this!

 

I'm gonna debate you on that one. It looks like excessive current draw (ie: should have used 1/0 ga vs 4ga) over a period of time. While running 12' of ground wire is not "ideal" that is not the case here.

 

How can you debate me on that? You don't even know what amps were in the vehicle... They could've only been pulling 20 amps of current for all you know. FYI, A Kenwood mono amp (35 amps of current with volume maxed at most) and a RF 4-channel (don't remember which model, but not anymore current draw than the Kenwood).

So please, you can't tell me that a 4 ft run of true CEA 2006 compliant 4 AWG power wire on a (at the very most) 70 amp circuit would cause an excessive amount of current draw, enough to scorch the power wire and melt the fuse holder. Additionally, the fuse was still in-tact and not blown, the only thing that saved this car was the fact that the fuse holder had melted, breaking contact with the battery.

Don't debate when you don't know the facts. Its ignorant. Sure, question me, and I'll give you the facts...

Hey, I got this for you...

 

Calm down...no need to turn this into a pissin' match. Your right I don't know what amps were used. But based on what you presented I'm betting 2 amps with a potential draw of about 120amps under those conditions-kinda like sucking a shake through a soda straw. Enough to get some flowing but working harder to do so...that's why it (the fuse holder) heated up...but did not blow the fuse. Kirchhoff's law still exists...

Oh by the way...my CEA # is 111900 (advanced)...soon to be master ( I'm lazy). As stated not turning it into a pissin' match....i just saw something different. I agree with your original post (plus I'm the guy who states that "mice chasers" (noise filters) are band aids.

 

I can **** further, bi**h! LOL, Im kidding...

Sorry about that, I know I sound like a dick, it just seems that there are sooo many ppl that think they know what they are talking about, but can't back up what they say. It gets old. I mistook you for one of those ppl... I can see why it would be easy to assume that we had a high current application, when all you hear is that two amps and a cap were installed...

 

joey, since you sound like you know your way around the business, if you dont mind i have a question related to your post. I have a pioneer AVIC D2 with terrible whine only sent through the 4ch amp (sub amp still works and sounds as it should). I have tried grounding the rca shields as everyone says to do for a "bandaid", and it works a little bit, but still getting the whine. I had to resort to just pulling the 4ch amp and running the components off the hu power.

And my question... I am under the assumption that either my pico fuse or a ground inside the hu is bad. Do you know of a reputable shop that can fix this for a reasonable price? right now, my only 2 options are pioneer and a shop i found up in NY, however both have a $200 flat rate fee, which seems a bit nuts for a few solders. Im in NC, but realize i will likely have to ship for this, and im ok with that. just want to get this thing back to normal, and not drop 200 on a 5 year old hu.

Thanks!

 

I can't give you a 100% factual answer on that. From experience, There were a cpl pioneer model from around the time of the d2, including the deh-p7800mp, and higher models from the preamps. It was due to resistance to ground in the preamp, and what most ppl were doing was wrapping non-insulated wire around the preamps, one wire, circled around all 6 preamp jacks at the radio, and grounded with the radio ground behind the dash. It fixed most ppl's issues. In this case, If your 4-channel has a high level input, you could run high level output from the d2 instead of using the preamps with RCA's... The high level outputs are completely independant from ground, and that should solve your issue without spending $200 and having down time with the d2 for shipping... To be honest, I'd be willing to bet that there is actually noise through your sub preamp also, but your lowpass filter on the amp filter's it out, so you can't hear it through the sub... I'd prob start a new thread on this topic if I were you, maybe you can get a better answer than I can provide...

 

If you don't Have high level input on your amp, you could run line output converter (AKA : LOC, hi-lo converter, premium system interface) right behind your radio, and still use your RCA cables to your amp. As far as the model deh-p7800mp, I could be wrong on the year it was sold, I can't remember off the top of my head, but I believe those bad preamp outs started with the 7000 series radios from that year. As far as repairing the actual unit, I couldn't answer that. I always send product that require service back to the manufacturer...

 

The Pico fuse on the rca ground "popped" which is causing the whine. Honestly its a very common problem with the higher model pioneer units. Its done that way to eliminate damage to the preout circuitry in case there is a grounding issue (yes 12v sources a negative return point every time).

 

x2...this thread should read "99% of the time it's your pioneer head unit and the pico fuse is blown" lulz....

thus me not agreeing to the statement of cheap audio equipment being the main culprit as it's the higher end model premiers and alpine units that have this problem...as did my p860mp...24-bit burr brown dacs...active unit...very nice and my 9886...just grounded my rca's to the chassis of the HU to fix issue. though the right way would be to replace the pico fuse

 

i was getting feed back on my stero with the car off . i found out it was my wide band o2 when is conneted the stereo has feed back but when i unplug it, it goes away what could be the problem... bad ground? the stereo is grounded thru the wiring harness and the wide band is grounded underneath the steering colunm.

 

No, this doesn't sound like a bad ground. It sounds like yoour wide band is still active with your ignition off. Bc you actually have good grounds, with very littly resistance btwn the two grounds, and that wide band o2 staying active, there is current bleeding from your wide band into your stereo ground, causing the noise.

 

Just wanted to add this to the rant: There is a school of thought that your ground wire should be as long as your power wire... That's kinda true, some ppl just take it too literally.

Remember that your car chasis is a conductor? Well, if your ground wire itself is only 18" long, but it has a direct connection to the chasis, how long is that actual ground? It actually does run up to the (-) battery terminal in this case, huh?... YES... (no need to run your ground wire to your battery).

We really want to consider this rule with vehicles that do not have a chasis that is used as a conductor, such as an exotic vehicle with very limited steel chasis (when a lot of fiberglass or carbon fiber is used to fabricate the body), or a boat which has a fiberglass/wood/foam hull... In this case, absolutely, the general rule is to run your pwr and ground conductors equal distances....

 

omg TONS of good info in here.