weird ringing sound after amp install.

[jeyventura 10+ year member]

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thats what you need scoche is garbage

 

[Xenozx 10+ year member]

These are the RCA's I am using. These are the ones running to the amp currently.

Scosche ERCA9 - 7-12 Ft. (3 Meters) - Sonic Electronix

now to to mention, I did try a heavy duty set of RCA's and they were not ran through my car, I had the headunit out and in my hand, I plugged the heavy duty RCA's into the amp under my drivers seat, and then plugged them into the back of the head unit. They were not running through the car or next to any power/ground wire. Still had the same issue. I also tried 3 other sets of RCA's all had the same problem, all were not ran through the cars interior, just simply walked out to the car w/ RCA's in hand, plugged em into amp, and then plugged into headunit, and sound was there.

 

[jeyventura 10+ year member]

what kind of heavy duty rcas ???

most of them are not shielded

is you head unit pioneer ? some of them are known for having a bad ground

now try this tomorrow use those rcas from monoprice the ones you use for the computer to connect the head unit to the amp i know they look short but im sure the noise will go away if it does then you know what the problem is

im going to sleep let me know if that helps you

 

[traksta15 10+ year member]

have you tried grounding the headunit out? My kenwood started givin me horrible alternator whine so I just wrapped wire around my rca's and grounded to the back of my headunit (on one of the screws) like this:

 

[Xenozx 10+ year member]

The biggest issue w/ grounding the head unit, is pioneer does their RCA's like this:

I have four things I am going to try tomorrow to try to identify this problem.

1.) buy a 4 channel amp from bestbuy (to return later) and use it to test to see if maybe the rest of my setup just doesnt like the alpine PDX 4.100 amps.

2.) Ferrite cores, I am going to see if I can pick up a couple snap on ferrite cores and snap them onto my power cable coming from the battery and maybe the RCA's too if I can find them small enough.

3.) Ground loop isolator from radioshack (i had a friend of mine look at the ground loop isolator and the shield of the RCA's attached to it dont even look connected

4.) try a different power wire. This is really the only variable I havent taken out yet. I have a 4 gauge wire running from my + battery terminal to a Distro block. the rockford distro block then splits that and runs 2 4 gauge cables off to both my amplifiers. My sub doesnt have this noise at all. The inside speakers do.

 

[Wingman0121 10+ year member]

If the noise changes with engine RPM and/or anything that's operated in the vehicle then yes it is picking up noise through wires(most likely power wires), it could be anywhere from the power wire to the actual wiring harness behind the dash, especially if you have other electronics nearby such as an aftermarket turbo timer or rpm counter.

What are you doing with the loose wires behind the dash or in the trunk? You're not zip-tieing them in tight circles or something right? Whenever you coil wires together you create inductance.

 

[Xenozx 10+ year member]

I cut the wires as short as I could, and then electric taped the tips.

I had a wideband gauge and a boost gauge, but I have since disconnected them (they are not hooked up) but I still have the sound.

Only thing that makes me think its not that, is I had a pioneer amp before the alpine, and using those same RCA cables in the same location, I had no issues. It

was only after I swapped out the amplifier and the power/gound cable (same locations but changed from 8 gauge for 4 gauge) that I had a noise.

could it be a crappy power cable? Do they make shielded 4 gauge power cables? would a ferrite core fix that?

 

[Wingman0121 10+ year member]

Well thicker wire can pick up more interference than small wires but usually it isn't a problem, they don't make shielded power cables... but I've heard some SQ guys who run their wires inside copper tubes from house plumbing.

Those Scosche RCAs aren't all that great but I have the exact same pair sitting in my house and I have no problems with it in two different cars.

So no noise when you use your MP3? Is it hooked up to your HU's aux input?

 

[Xenozx 10+ year member]

no noise when I hook my Mp3 player up directly to the amp using RCA's.

 

[Wingman0121 10+ year member]

As far as the headunit's wiring harness... is the black(ground) wire hooked up to the factory harness or grounded to a nearby metal surface that's connected to the chassis? Is the ground wire in the stock wire loom seemingly smaller than the wire from the headunit? You said when you touch the center pin to the shield the noise goes away, but obviously you wouldn't be able to play music then.

As this point you can try to ground the headunit somewhere else, but it seems like it's some sort of weird electrical interference problem that really needs to be looked at hard, which means tearing everything apart.

If it worked before then it's definitely fixable.

 

[Xenozx 10+ year member]

yea, I tried grounding everywhere, ground wires in the harness/headunit are about the same size. I also ran the ground from the headunit and amp directly to the battery to see if that made a difference and it didnt.

I am going to pick up some monster RCA's. Found some Extreme low noise ones for 26 bucsk shipped, (4 channel 9 feet long) so I think those will do the trick.

I have read a few review about the PDX 4.100 about it being very noise happy w/ crappy RCA's, and maybe all the RCA's I have even the mono price ones are not shielded enough.

im gonna swap out the amp tomorrow w/ a bestbuy one, as a test, ill update after that.

I probably wont get the RCA's until Tuesday/wednesday.

 

[jeyventura 10+ year member]

im back wanted to see what happen dude listen to me its your rcas thats it get some nice shielded ones and that should get rid of it dont waste your money in ground loop isolators its just like a bandaid

 

[Xenozx 10+ year member]

I am pretty sure I figured out what the problem is. My understanding is all pioneer headunits use Pico fuses and I probably blue them. My sound from the headunit sounds like shit, me and my brother ripped the car apart (and fatmat'd the rear deck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ) and re-ran the power wire on the other side of the car. We connected it much neater w/ a gold plated positive terms. We re sanded all ground locations, we bought ferrite cores and added them to both ends of the RCA's, and tried thick *** mono price RCA's. we were able to get the hum noise almost completely gone. Unfortunatly most of the sound from my music was gone too. We could pull the RCA's from the deck, and plug them into my 1GB mp3 player and the sound was awesome, and hum free.

Needless to say, I read that pioneer decks have pico fuses that can be blown very easily if you pull RCA cables while the deck is powered up. Well i did that about 100 times while trying to figure this out, and may have done it when I swapped amps, and that may have been my cause right there.

needless to say, replacing/bypassing the pico fuses are a *****, so I may be forced to send this back to pioneer for replacement/repair. So no headunit/sub for the next few weeks is my guess.

 

[jeyventura 10+ year member]

lest see what happens when you get the new head unit

 

[BassElementz 10+ year member]

i skipped a few posts but if u havent already tried this then try grounding your rca's