Page 2 of 6 FirstFirst 123456 LastLast
Results 11 to 20 of 56

Thread: Ewww, ground noise finally isolated, now wut!?

  1. #11
    _
    Join Date
    Mar 2004
    Location
    Little Elm, Texas
    Posts
    13,500
    if the grounds are 100% then it's the amplifier.

    how old is this amp? how long have you had it? did you buy it new or used?
    Jan Bennett
    FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

    Please post on the forums! Chances are, someone else has or will have the same questions as you!

  2. #12
    FLAC sdashiki's Avatar
    Join Date
    Aug 2004
    Location
    Floreeda
    Posts
    1,084
    its at least 5yrs old now. i bought it used, but it had no noise like this in my last car. and the only reason i didnt notice it in this current car (4yrs and counting) was until I had installed the new components in the rear. Now with all my highs coming from ear level, as opposed to foot, its really easy to hear the noise.

    Ill still check it with a MM, by the way where should I be testing the resitance? One probe on the neg. terminal on the amp and the other to the bare spot on the chassis I chose as my ground?
    (0.0%-) starting over
    iPad 3G 64GB, RF 600.5 amp, JL10W0V2, 8 Infinity Components

  3. #13
    FLAC
    Join Date
    Sep 2004
    Location
    Falls Church, VA
    Posts
    904
    This is interesting and i have to agree its the bad ground. What other damage has it caused?

    First thing- lets cut out RFI as a culpret. Make a set of grounding plugs by cutting a set of RCAs to a couple inches and shorting the inside wire to the outer shield. Plug em into the amp and turn em on. If this makes the noise go away then you have an RFI issue where something near the amp is causing some serious noise.

    Im guessing that is not it. Get yourself a multimeter and check the outputs of the amplifier. I want you to check for any dc voltage coming out at idle. If you have DC, you have a problem. Now check the grounds of the RCA inputs. Check to see if you have continuity between the outer shields of the RCA inputs. You hold one proble on outer ring of one rca input and the 2nd on another. Check em all. They should all have continuity. If you find one does and others do not, then you have burned out some grounds.

    Regardless, Im betting that a poor ground caused some issues. Probably shorted out the grounds on the input section. You may have shorted the grounds on your head unit as well. This one is tough to reproduce in a shop...

  4. #14
    FLAC sdashiki's Avatar
    Join Date
    Aug 2004
    Location
    Floreeda
    Posts
    1,084
    Well the amp is isolated as it is.

    No RCAs going in. Only speaker wire going out to front/rear/subs. And the noise is there when the car is on.

    So its not the HU at all.

    Where should I be checkin with the MM to see if the ground connection is poor?
    (0.0%-) starting over
    iPad 3G 64GB, RF 600.5 amp, JL10W0V2, 8 Infinity Components

  5. #15
    FLAC TheLlama's Avatar
    Join Date
    Jul 2004
    Location
    All over the world
    Posts
    970
    try getting a noise isolator at wal-mart for $15. I think they are made by Scotsche or something. It is basically two big coils that pass sound from one to the other via inductance. It may degrade sound quality some, but it is a good test. For $15 you can keep it if it fixes the problem and sounds good or just return the thing.

  6. #16
    Constant Bitrate Specimen's Avatar
    Join Date
    Jul 2005
    Location
    Los Angeles, CA
    Posts
    153
    Just trying to get a feel for your setup. You said there's crossovers connected between the amp and the speakers, how and where are the crossovers grounded. Did you just install these crossovers? The loop could be the grounding difference between the crossovers and the amp. Maybe try removing the crossovers in the setup and see if you can still hear the whine. Also how long is your ground wire from the amp to ground? I'm sure you've already tried to make it as short as possible but I always ask this when there is a ground loop issue.

    I know that might not be the problem, but I'm just trying to think outside the box. Also since the high frequencies were near your feet, you might not have heard it before like you said since high frequencies are not as omnidirectional like bass. Having them point to your ears now you will hear the whine more than before.
    PROGRESS [==========-] 99.9% <- Are we ever really actually done with our carPCs?

  7. #17
    Maximum Bitrate SAScooby's Avatar
    Join Date
    Feb 2004
    Location
    Johannesburg, South Africa
    Posts
    535
    the other possibility is you have a speaker thats grounding
    the speakers need to be 100% isolated
    check that out
    get a multimeter and begin some tests on the speakers, unplug each speaker and check if unplugging one of them one by one makes the problem go away
    Nano ITX / 512 MB / 60 GB / Panasonic slot load / M1-ATX / Bu303 / Sound blaster 24 / PPi amps / rockford sub

  8. #18
    _
    Join Date
    Mar 2004
    Location
    Little Elm, Texas
    Posts
    13,500
    how old is the amplifier?

    did you buy it new or used?

    I'm thinking that the amplifier is shot
    Jan Bennett
    FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

    Please post on the forums! Chances are, someone else has or will have the same questions as you!

  9. #19
    Well, He asked for it. WebDog's Avatar
    Join Date
    Sep 2004
    Location
    Los Angeles, CA (West LA)
    Posts
    1,636
    Quote Originally Posted by Red GTi VR6
    how old is the amplifier?

    did you buy it new or used?

    I'm thinking that the amplifier is shot
    he said on the last page
    Quote Originally Posted by sdashiki
    its at least 5yrs old now. i bought it used, but it had no noise like this in my last car. and the only reason i didnt notice it in this current car (4yrs and counting) was until I had installed the new components in the rear. Now with all my highs coming from ear level, as opposed to foot, its really easy to hear the noise.

    Ill still check it with a MM, by the way where should I be testing the resitance? One probe on the neg. terminal on the amp and the other to the bare spot on the chassis I chose as my ground?
    1990 Jeep Cherokee
    2000 VW Golf TDI 4dr
    2005 VW GTI MKIV - SOLD

  10. #20
    FLAC sdashiki's Avatar
    Join Date
    Aug 2004
    Location
    Floreeda
    Posts
    1,084
    Well a tiny update is that I notice that no matter what the volume is, the sound level of the whine/static is exactly the same.

    My setup:

    Name:  car.jpg
Views: 186
Size:  27.7 KB

    crappy quick sketch but its almost in correct placements as to where in the car everything is. front crossovers are under floor mats in front of where passengers feet go. the rear crossovers are underneath the back seat.

    the amp is attached to the top of the sub box which is behind the rear seats, its a hatchback.

    power and ground run on drivers side, RCAs and speakers on the passenger.
    (0.0%-) starting over
    iPad 3G 64GB, RF 600.5 amp, JL10W0V2, 8 Infinity Components

Page 2 of 6 FirstFirst 123456 LastLast

Similar Threads

  1. The quest for no noise
    By mp31500 in forum General Hardware Discussion
    Replies: 26
    Last Post: 04-02-2007, 10:12 PM
  2. Noise!! AARGH!
    By sq_geek in forum General Hardware Discussion
    Replies: 23
    Last Post: 09-21-2004, 01:33 PM
  3. Learn and fix ground loop noise
    By 14.4vTech in forum Car Audio
    Replies: 3
    Last Post: 07-03-2004, 08:55 PM
  4. stupid ground noise!
    By EvilInside944 in forum General Hardware Discussion
    Replies: 2
    Last Post: 08-14-2002, 10:29 PM
  5. Alpine / PC Challenges all around...
    By acitrano in forum General Hardware Discussion
    Replies: 5
    Last Post: 11-10-2000, 07:45 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •