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  1. Join Date
    Feb 2007
    Posts
    533
    #1
    Hi audio peeps! I need advice. I just received my 900W PA D5000.5 amp from Amazon and installed it yesterday. Before the installation of the PA D 5-channel amp, I had our temp amp (an old 300W Fenton 4-channel to power my MM6501 seps (front) and DB651 coaxials (rear) - no sub yet. With the temp amp, I had no noise besides the high-pitched powering off sound when amp is turned off

    But with the PA D5000.5 amp, I'm getting some hiss/whine even if:

    1) Radio is OFF (same scenario if my volume is set to 0 or fader/balance set to extremes)
    2) RCA inputs are NOT plugged to the amp
    3) Engine is OFF (I get engine whine in addition when engine is on).

    Here's the thing: when I turn on the radio and adjust the radio volume/fader/balance so a speaker plays a sound. The hiss from that particular speaker is gone even I turn the radio off (and on again) afterwards or just the particular speaker "off" using fader/balance controls. This is true even when I start the engine.

    But any speaker that hasn't played a sound since initially switching the car from OFF to ACC will have the hiss/whine

    The hiss doesn't increase with the volume.

    NOTE: My remote on wire is connected to the car's ACC so the amp turns on immediately even when my radio is OFF. Unfortunately, my factory head unit doesn't have a remote out.

    But then again, with the temp amp, this doesn't matter, I don't have this noise at all.

    What to do?

    We're thinking of the following possibilities:
    • Static
    • Amplifier Ground Cable placement (Gauge 4 na as it is) - With the Fenton it's OK but with the more powerful Polk hindi siguro?
    • Other Ground? - Kaso hiss is there even when the RCAs are unplugged
    • Defective Amp - Huwag naman siguro, I had this shipped from the US

  2. Join Date
    Feb 2007
    Posts
    533
    #2
    [UPDATE] Let's say the car is on ACC with my HU off and I am getting this buzzing sound. If I open the driver-side door, I get this alarm that my key is still in the keyhole. This is pretty standard for most cars now. But once I close the door, the alarm stops.. AND so does the buzzing from speakers

    Previous Amp:



    New Amp:


  3. Join Date
    Jan 2009
    Posts
    5,577
    #3
    Does your stock radio have a power lead going to a motorized antenna or an active antenna pre-amp system? If so, you can use that as the remote amp trigger.

    If I would venture a guess, I would think that it may have something to do with the input automatic gain. With no signal coming in initially at the inputs, the amp may have automatically increased the gain to compensate. But when you turned on the radio, the amp readjusted the gain to a lower level, almost eliminating the white noise.

    As with the connection with the door closing, I would think that there was enough spurious or transient noise coming into the input, possibly caused by the dome light control circuit, to introduce a "pop" into the amp input and allowing the input gain to adjust its level.

    The best workaround is to somehow tie up the remote power to the HU.
    Last edited by oj88; January 12th, 2013 at 12:37 PM.

  4. Join Date
    Feb 2007
    Posts
    533
    #4
    My unit have the fixed antenna on the middle of the tail-end of the roof so motorized antenna is out. I'm not sure about the active antenna pre-amp system. My installer said he can't find a remote turn on wire. I'm inclined to believe him.

    I did buy an active LOC Audio Control LC2 which has a remote turn on feature for HU's without the remote turn on functionality. I'm just waiting for my subwoofer so everything will be installed one-time. I just couldn't wait and installed the amplifier first since it's just removing and reattaching of the individual wires from the old amp to the new amp. I'll have my amp checked out at the same time na din.

    I'm just wondering why my old amp doesn't have this noise but the new amp has it is the "automatic gain adjustment" a new feature of new amps? could it be turned off?

  5. Join Date
    Feb 2007
    Posts
    533
    #5
    Just an update guys, hoping someone can give suggestions?

    So I went back to the installer for subwoofer installation and at the same time, get them to help me resolve my issue.

    The first thing we did was remove the amplifier from the car and connect it to a test speaker and battery away from the car. Each individual channel was good and no noise. So that rules out the amplifier

    When brought back to the car and connected to my speakers and power connections, the noise is there, obviously.

    So I wanted to pin-point the issue so we tried different combinations when the amp is already connected to my car's audio setup and found out that if the amplifier's power, ground and +12v remote are directly connected to an external battery, the static noise is NOT present.

    However, when the amplifier's power and ground was connected to the external battery BUT the +12v remote was connected to my car's ACC, the noise was there. This led us to a faulty conclusion that its a problem with my remote write connected to the car's ACC tapped from the HU, so I asked the guy to tap the remote wire to another source directly in the fuse box. To our hearts dismay, the problem was still there

    Next, we tried connecting the ground directly to the battery using jumper cables hoping to eliminate any grounding issues. The noise was still there. However, now that I am reflecting on it, the guy connected the jumper cable to the end of my existing ground wire. Were as when we connected the amplifier to the external battery, we used a different set of wires.

    I might go back and ask them to use the jumper cables directly and use a new set of power wires to eliminate if its my power and ground wires and their placement

    Any more troubleshooting ideas is certainly appreciated

    PS. The guy used a volt meter to check the voltage of the power+ground and the remote+ground, the result came up with a stable +12.4v.

  6. Join Date
    Jun 2006
    Posts
    2,605
    #6
    It is most likely your remote on wire. It really should be connected to your HU. Some things to check:
    1. Is your ground connected to bare metal? You really should scrape the ground point to metal and remove all paint for a proper ground.
    2 Are your wires and cables free from connections (dugtong)?
    3. Are your rca and power cables away from each other?
    4. Has your installer checked for ground loop?

    You have a very nice amp. Sucks that its giving you problems. BTW, who is your installer? Static is a pain in the behind to trouble shoot. Maybe you should try some other shop or installer.

  7. Join Date
    Jan 2009
    Posts
    5,577
    #7
    If I would try to make sense of it all, it now appears that your car's electrical system is introducing the noise. Modern cars usually have at least two computers that may be introducing EMI/EFI or even RFI to your electrical system.

    The more common of these computers is the ECM/PCM, This takes care of engine control and emissions. The other computer is usually called the in-cabin computer and it handles driver aids like controlling the central locking system, power windows, wipers, dome lights, horn, keyless entry, etc. A third computer or more computers may exist depending on the car (ie, SRS, etc.) These computers talk to each other using a single strand of wire, pretty much like how computers talk to each other through a LAN cable. Different cars use different protocols and communication methods.

    On my Civic, the in-cabin computer is proprietarily called the MICU or Multiplex Integrated Control Unit, and it talks to the other systems like the ECM, SRS, immobilizer system, and the dashboard instrumentation using the BCAN (Body Control Area Network) and FCAN (Fast Control Area Network) protocols. One minor function the MICU does is to give the driver the ability to roll-up/down the windows for a predetermined amount of time AFTER you've turned off the ignition. During that grace period, the MICU is powered up and active. When the timer runs out OR if I opened any of the doors, that feature is cancelled and the MICU immediately goes to sleep/inactive mode.

    In your earlier post, you mentioned that the noise goes away whenever the driver's door is opened. This could be a clue that your inboard computer is generating that electrical noise. If you know a friend of a friend whose friend owns an oscilloscope, you'll be able to see if the noise is local to the car's electrical system (meaning, it is being caused by one of the computers or accessory) or if it's being picked up as RFI (like the car's electrical system acting like large radio antenna).

    Now, If the noise is indeed caused by any of your car's built-in systems, you typically have no other recourse but to employ a noise filter for your amp. I can't tell you how or where to get it as I've never even imagined needing it up until I read about your problem.

    Again, I'm just spit-balling here so take these comments with a pinch of salt.

  8. Join Date
    Jul 2010
    Posts
    570
    #8
    Try installing filter capacitor around 0.1 microfarad in your remote wire. This is to bypass high frequency signal ( hiss ) to ground of your Remote Wire. This will help cleaner Remote Wire.

    But if hiss noise still persist.
    Try installing separate high current relay for your amplifier as dedicated power source and use bigger gauge wire. Ground wire connection must be also in the battery - terminal. Don't forget the fuse.

  9. Join Date
    Feb 2007
    Posts
    533
    #9
    ^ I don't know if I know a friend who knows a friend who knows a friend that has that But thanks a lot for the informative post I'll leave any interference as the last possible explanation. For now, I will follow this guide: Noise Suppression Guide - Noise Suppression Guide.

    I uploaded an MP3 file for you guys to hear the noise yourself: Playing: Static Noise - Door Open-Close.mp3 - picosong

    Here's a summary of the significant events by time:

    0:02s - I switched the key from OFF to ACC
    0:08s - Amp clicks ON
    0:09s - Static noise comes to life!
    0:14s - Opened the driver-side door
    0:15s - Annoying but perfectly normal door alarm
    0:18s - Closed the door
    0:19s - Static noise gone!

    The entire time the head unit is OFF. If I turned ON the HU and it starts sending signals, the same effect as the door closing will happen.

    Quote Originally Posted by userfriendly View Post
    It is most likely your remote on wire. It really should be connected to your HU. Some things to check:
    1. Is your ground connected to bare metal? You really should scrape the ground point to metal and remove all paint for a proper ground.
    2 Are your wires and cables free from connections (dugtong)?
    3. Are your rca and power cables away from each other?
    4. Has your installer checked for ground loop?

    You have a very nice amp. Sucks that its giving you problems. BTW, who is your installer? Static is a pain in the behind to trouble shoot. Maybe you should try some other shop or installer.
    #1 - I had it scraped but it might not still be enough. I'll ask them to do it again if we can isolate that the ground is THE problem.

    #2 - Yep. The noise isn't coming from one speaker, it's coming from all speakers.

    #3 - Yep. The remote wire is kinda close to the RCAs. However, when I unplug the RCAs the noise is still there. So the noise is unlikely caused by my HU and LOCs.

    And yeah, it sucks bigtime. My installer is a very reputable (and costly) one and so far, they're willing to diagnose my problems. I think I'll stick with them first

  10. Join Date
    Feb 2007
    Posts
    533
    #10
    Quote Originally Posted by Chinoi View Post
    Try installing filter capacitor around 0.1 microfarad in your remote wire. This is to bypass high frequency signal ( hiss ) to ground of your Remote Wire. This will help cleaner Remote Wire.

    But if hiss noise still persist.
    Try installing separate high current relay for your amplifier as dedicated power source and use bigger gauge wire. Ground wire connection must be also in the battery - terminal. Don't forget the fuse.
    Yes sir! Will follow once I convince my installer and his electrician that the issue is NOT with my source but with the power, ground and remote wires. I already have Gauge 4 (Audiomax) wires.

    More pics to help visualize:

    Battery Connections


    Active LOC sourcing fronts and sub


    Gauge 4 Power and Ground Wire


    Amp Ground Location


    We used the same ground location. Right now, the same grounding point we use for (1 being the closest to the chassis):

    1. Amp Ground (Gauge 4)
    2. Active LOC (Gauge 18)
    3. Factory Ground for something (we don't know what)

    Power and Ground


    I asked them to add a chassis-to-negative-battery connection on the other side of the stock position. We used the same bolt as the bolt for the alarm siren.

    Power wire crosses the engine along the firewall and runs through factory grommet on the passenger side leading to the back of the glove compartment.

    Amp Position


    Amp positioned nder the passenger seat. Amp ground wire runs more or less than 1 yard from amp to chassis.

    I can post more pics if necessary

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Amp Hiss (even when RCAs unplugged; disappears when sound is played)