noise introduced through rca wires

Discussion in 'Car Audio Head Units' started by BigWizzleFoShiz, Nov 19, 2006.

  1. BigWizzleFoShiz

    BigWizzleFoShiz Full Member

    My stereo is a pioneer, its an older model mp3/cd player. And I first installed it into my jeep cherokee 1987.and I got an amp and hooked it up, at first there was no noise and after a while a constant thumping noise was reverberating through my subs. i got a noise filter this seemed to help the problem but just made the noise quieter and also my music coming through them. Later I got a Honda accord, and it had the same problem, though a different noise.

    (it sounds like the engine is being amplified through the subs. but it does not come through the HU amp tho). Anyways I got tired of the noise so I tried using my girls HU, bad idea same thing happened to it. Now hers does it, Which i also installed a rca noise filter. helps but doesnt fix it. The main reason why i am having problems is because. the sound coming from the HU is not as loud as it used to be. speakers used to sound powerful but now sound like their signal is not strong enough even though it is still pretty loud.

    if someone could please help i have been having this problem for about a year now.
     
  2. Hautewheeler

    Hautewheeler Full Member

    sometimes amps go bad..

    have you tried using a different amp? - you said that you have used different vehicles, and a different head unit..

    I did have an old sony hu that did the same thing until I blew it up with some firecrackers.
     
  3. BigWizzleFoShiz

    BigWizzleFoShiz Full Member

    yeah its not the amp, if i deisconnect the rca's it goes away even hooked upo house stereo rcs no problem
     
  4. Hautewheeler

    Hautewheeler Full Member

    wow this is deja vu..

    the amp has an internal noise filter, because all electrical systems generate electrical "noise".

    when that goes bad, it "amplifies" the noise that is coming from the engine's electrical system, rather than cleaning it up.

    try this.. make sure that your rca's are not running right alongside the power wires for the amp. this will cause noise distortion.

    make sure that your big three are solid
    battery negative to chassis ground
    engine to chassis
    and battery positive to amplifier

    sometimes noise is cause by a bad ground here, and typically these wires are cheap little ground straps made from flat braided wire.

    make sure you are using decent quality rca's and not magnavox. cheap rca's go bad often, but they won't "cause" noise, just transfer it.

    might be easier just to try a different amp first, and see if you still notice the sound.. either way, take care of the big three.
     
  5. Ranger SVO

    Ranger SVO Full Member

    Noise is so difficult to locate and fix without having the car here to look at. Everyone always blames the ground, but this is not always the case. To reduce noise manufactures usually float the shields above ground, and that is where the problem starts. Different manufactures float the ground differently.

    I was recently reminded of that when I changed an amp in my truck. My truck was completely noise free and then I replaced an amp, using the same existing power wire, the same existing grounds, the same RCA's, in fact the amp that was replaced was a Kenwood and the new amp was a Kenwood. All of a sudden I have an RPM gauge that I could here through my speakers. And it was loud.

    The problem was not a bad ground, it was a potential difference in the grounds. Both the radio and the amp have grounds to the vehicle chassis. Filters don't fix problems they mask them.

    Now in my case it was as simple as running an 18 ga wire from the chassis of the radio to the chassis of the amp, the noise is completely gone.

    To fix noise you will need a DVM and a basic idea of what to look for. I do all my measurements with the negative lead of the DVM hooked to the batt neg. This way all my measurements are with respect to a single ground. Now look for the difference, thats your noise problem.

    In most cases its easy to find, but I have run into an interesting case once in a great while. Lose any noise filters while you are looking for the problem.

    Of course always do the obvious first, make sure the grounds are solid, if the radio is using a factory ground, cut it and go to the chassis if the car. Disconnect the antenna to make sure the radio is not grounding through it (antennas make terrible grounds).

    Throttletune posted a method recently on a quick way to check grounds, with every thing turned on set the DVM to volts (neg lead attached to the batt neg, everything with respect to battery) and check to see if there is any voltage on the amps negative lead. I don't recall what he said was acceptable, but if you have a 1/2-volt its too much.

    At this point properly diagnosing the problem will yeild a solution. I wish I could be more help
     
  6. TheViking

    TheViking Well-Known Member

    Glad to see you back in action around here Ranger!

    Ya, that is one way to start the process....... and a good one at that.

    If ya wanna try other things, i will also help out the process too a point, like was said, without the cat actually being in front of me in my shop, its hard to trace these things dowm at times.

    Try some of these basic procedures...


    If the noise goes away at any one of these let us know...


    Disconnect RCA's from radio

    Disconnect RCA;s from amp

    Unplug antena lead

    Noise gets worse when you turn on the lights and wipers and blower at the same time

    Thats a starting point , let us know what you find......but if you have and know how to use a DVM, do what Ranger said also........Need a baseline to go from on these things....
     
  7. BigWizzleFoShiz

    BigWizzleFoShiz Full Member

    Noise

    Ok,

    before i went to work today i ran wires directly from the battery to my stereo, and had no luck. i then disconnected the rca noise filter (it is a set of grounded rca's) and the noise is obviously not the car engine it makes the noise when the car is turned off. but it sounds like a car engine. the noise goes away when i disconnect the rca wires from the hu or the amp, tried both ways. the antenna is allready disconnected i did this a while back because i thought it helped somewhat? and the noise doesnt get worse with the wipers/blower on.

    the noise is somewhat tolerable to a point that i wont stop using it. it pounds really hard . the bass probably hits as hard as it would but not as clean. by the way i have a pioneer deck, kenwood 12's, and a sony 1200 watt xplod, in a poreted box with the ports blocked with fabric

    i was thinking about a sony deck - go or no?


    i took the noise filter off for the time being, it didnt really help just made the signal to the amp weaker.
     
  8. Ranger SVO

    Ranger SVO Full Member

    I went back and read your first post, and saw no mention of the noise problem with the engine off.

    What you are describing is an amp problem. Without hearing the noise, I am guessing the amp is going into oscillation (don't know if its the right term), if so replace the amp.

    I don't like throwing money at a problem so have a shop check the amp. Let us know whats up, but I suspect the amp.
     
  9. TheViking

    TheViking Well-Known Member

    ditto............
     
  10. BigWizzleFoShiz

    BigWizzleFoShiz Full Member

    noise gone

    well, i saw the sony decks on sale 35% off and grabbed me the nicest one. works fine now no noise whatsoever and i have a 3rd rca for my subs :lol: . just thought i would let you guys know because i had you stumped. pioneer car stereos just dont work for me, maybe premier but i cant spend any more money on em.
     
  11. DREAMZmustang

    DREAMZmustang Full Member

    i had this same problem i always heard the motor and the turbo running through the speakers
     
  12. Ranger SVO

    Ranger SVO Full Member

    Glad to here you found the problem, I'm still trying to figure out what could have gone wrong with the HU that you had.:confused:

    Anyway, glad its working for you
     
  13. thatyoungin

    thatyoungin Full Member

    i need help

    i'm having the same problems with my system. i'm using a Pioneer HU, the DEH-MP3900 which is only a month old, a Power Acoustik 520watt amp, 2 Insignia subs (which are bottom barrel Best Buy brand), and a Q-Logic Type 2 sub box(which makes those cheap A$$ Insignia's sound good). I bought another amp and had the same issues. i replaced RCA's also. now all there is to do is replace the HU. i've been thinkin, before i do that, i'm going check to see if it's my power wire being next to my RCA's that's creating the issue. i think that may be the issue because while i was connecting new RCA's i ran the new ones from the back of the HU directly into the trunk to see if the problem went away, and honestly it seemed to go away until i put everything back the way it was supposed to be. this might be an easy fix, hopefully it is. anybody know what i can use to shield my RCA's from my power wire? electrical tape? any thoughts?
     
  14. TheViking

    TheViking Well-Known Member

    Distance is your best freind!!!!! Keep those RCA's as far away as possible from ANY power wire! And electrical tape will not sheild an rca....
     
  15. aznboi3644

    aznboi3644 Full Member

    ..........get some aluminum foil and wrap your entire rca in it and it should shield it.........


    lol
     
  16. thatyoungin

    thatyoungin Full Member

    please tell me you're joking! who has that much patience? i'll just move the RCA's from one side to the other, lol
     
  17. TheViking

    TheViking Well-Known Member



    :ban: :bash:
     
  18. pedro quiroga

    pedro quiroga Well-Known Member

    funny azn....:lmfao:

    would be funnier if he did it............dont. by the way.
     
  19. thatyoungin

    thatyoungin Full Member

    ok, well its not that my RCA's and power wire are close, so now what? i noticed that the interference is a lot louder when the engine is running. i'm gonna check my grounds again, and then i'm takin it to best buy to see if its the HU f@!#$n' up. i think Pioneer may have a problem. this time we're goin alpine!
     
  20. thatyoungin

    thatyoungin Full Member

    after brilliant deduction, i figured out its my HU. i decided to use a line converter and run a signal from my rear speakers to my subs. worked fine. realized i bought another amp and RCA's for nothing. now i have to do something about my HU. i love pioneer but i think i'm going Alpine now. maybe even back to Sony, i never had any issues with those. one more thing is killin me though, i'm driving along, music pounding, i come to a stop and the subs started hitting way harder than before. not distorting at all, just way more vibrations. i felt it hitting hard in the front seat, which amazed me about the cheap a$$ subs i have. loose connection inside the box??? all the others are tight, i double-checked.