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  • UNHCLL
    replied
    The pop has resolved itself... by burning up the amp.

    Started the car, had no sound from the speakers, and proceeded to open the trunk to see lots of white smoke coming out of the amp.

    Took the amp to the local BA Authorized Dealer, and they discovered the following:



    Now I will have to call BA on Monday and see if they will cover this under warranty since the amp was purchased less than a year ago.

    To top it off, the head for one of the cosmetic cover screws also sheared off today. Right now Boston Acoustics is dangerously close to moving to the very top of my Black Listed Companies. I am none to pleased to say the least, and can only hope that when I call them Monday they resolve this in an expedient and corrective manner.

    Leave a comment:


  • Lionel
    replied
    Originally posted by UNHCLL View Post
    Great info, thanks Lionel! I have not checked the actual ground cable itself yet.




    I would be more inclined to up the wire gauge than drill/scrape new holes.
    I assume I should be avoiding connecting to the ground strap location on the body where the negative battery cable goes as well, correct?


    Thanks!
    -Chris
    Chris,

    Happy to be of help.

    In theory you are right about the battery stud, but may be trial and error until you find a good spot that gets you to the magic number of .5 ohms or less.

    I shyed away from bare metal as well. With my friends Silver M I used the tower locations, 2 amps with 4 gauge each gave and zero feedback. On mine I used the left side wheel chock location(stud) but I did up the wire gauge.

    Its all about getting to that no resistance spot that gets the noise out.

    As it is, it's a strange problem, and there may be more to factor out until we can get to the root cause.

    At least we have somewhere to start.

    Keep us posted.

    L.

    Leave a comment:


  • Mario L.
    replied
    No. I'm on the phone working!!! :yeah:

    Mario L.
    Last edited by Mario L.; 06-17-2009, 05:49 AM.

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by Mario L. View Post
    Since this only occurs when lifting off the throttle , NEVER LIFT!

    Hammer down!

    Mario L.
    Your office phone is off the hook.... :peekaboo::nope:

    Leave a comment:


  • Mario L.
    replied
    Since this only occurs when lifting off the throttle , NEVER LIFT!

    Hammer down!

    Mario L.

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by Lionel View Post
    Check the ohms on the ground wire itself with ohm meter. hold the leads of the meter at both ends of the ground wire(not the body just the wire). You should see no more than .5 ohms.

    This is considered a good ground connection, .5 ohms or less.

    Second Check the ends of the ground connection, Crimped 4 gauge is usually a bad connection, due to size(common problem they say), soldered to a connector is usually best.
    Great info, thanks Lionel! I have not checked the actual ground cable itself yet.


    Originally posted by Lionel View Post
    Ground contact must be bare metal to the body. Battery terminal is worst, studs or screws connected to the body aren't usually good either. This is why some use heavier wire on the ground side to elminate the resistance(ohms). I didn't want bare metal so I went heavier on wiring.
    I would be more inclined to up the wire gauge than drill/scrape new holes.
    I assume I should be avoiding connecting to the ground strap location on the body where the negative battery cable goes as well, correct?


    Thanks!
    -Chris

    Leave a comment:


  • Lionel
    replied
    Going back to basics, Any feed back, loop or noise can usually be traced back to the ground, 98% of the time.

    In talking to friends there is a sure fire method to checking your ground.

    Check the ohms on the ground wire itself with ohm meter. hold the leads of the meter at both ends of the ground wire(not the body just the wire). You should see no more than .5 ohms.

    This is considered a good ground connection, .5 ohms or less.

    Second Check the ends of the ground connection, Crimped 4 gauge is usually a bad connection, due to size(common problem they say), soldered to a connector is usually best.

    Ground contact must be bare metal to the body. Battery terminal is worst, studs or screws connected to the body aren't usually good either. This is why some use heavier wire on the ground side to elminate the resistance(ohms). I didn't want bare metal so I went heavier on wiring.

    Once eliminating the ground as a factor you're left with the wiring to the amp as one wire may be making contact and the amp is simply protecting itself or the amp itself may be bad.

    The pop may be generated by the amp itself or TPS, remember an amp converts low signals to high. The popping is ultimately generated by something and even though its speculation on the TPS, the fact that the noise is only on throttle response means something. On GM cars its common on the brakes(small pop w/bad ground and hitting the brakes).

    Hope this helps.

    L.
    Last edited by Lionel; 06-16-2009, 11:19 PM.

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  • Lionel
    replied
    Originally posted by UNHCLL View Post
    Gain has been turned almost all the way down, no change.

    The pop has no correlation whatsoever with powering on/off any of the components in the car, so I don't think the above is of any use... sorry Chicco!

    -Chris
    Wow, I did read into this wrong and so I am to blame for Chicco's response.

    Sorry Chicco, my response may have mis lead yours , but we tried.

    Down to amp-ground or amp internals and possibly sticky TPS, the sound may just be amplified and picked up as feedback with in the car.

    Also don't forget the pm.

    L.

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by Chicco View Post
    Hello:
    Here is a quick fix below, of a Passive filter other than buying an Active filter. The only other thing is how much gain is turned up on the amp? You may want to lower it.

    Relay turn-off pop is caused by components in the system turning off before the amplifier completely shuts off. In most cases, the component will be an EQ or signal processor. Usually adding a little turn-off delay to the offending processor can fix the problem. This allows the processor to turn off after the amplifier, preventing the pop. Many components have this feature built in, and it is adjustable. Check the manual to see if your component has this feature available. If not, you can build your own delay circuit with a diode and a capacitor. Add a 1N4004 diode in series with the processor's turn-on lead, striped side toward the unit. Then add a capacitor in parallel, the positive side of the cap connected to the striped side of the diode, the negative side of the cap to car chassis ground (not to the body of the radio or processor chassis). Experimenting with the capacitor value will give you just the right amount of delay before the EQ shuts off. You don't want the delay very long, just long enough to make sure the amp is off before the EQ powers down. Usually 220 - 1000uF is about right. Make sure that the cap is a polarized electrolytic, 16V or higher.

    Regards,
    Chicco
    Gain has been turned almost all the way down, no change.

    The pop has no correlation whatsoever with powering on/off any of the components in the car, so I don't think the above is of any use... sorry Chicco!

    -Chris

    Leave a comment:


  • Chicco
    replied
    Hello:
    Here is a quick fix below, of a Passive filter other than buying an Active filter. The only other thing is how much gain is turned up on the amp? You may want to lower it.

    Relay turn-off pop is caused by components in the system turning off before the amplifier completely shuts off. In most cases, the component will be an EQ or signal processor. Usually adding a little turn-off delay to the offending processor can fix the problem. This allows the processor to turn off after the amplifier, preventing the pop. Many components have this feature built in, and it is adjustable. Check the manual to see if your component has this feature available. If not, you can build your own delay circuit with a diode and a capacitor. Add a 1N4004 diode in series with the processor's turn-on lead, striped side toward the unit. Then add a capacitor in parallel, the positive side of the cap connected to the striped side of the diode, the negative side of the cap to car chassis ground (not to the body of the radio or processor chassis). Experimenting with the capacitor value will give you just the right amount of delay before the EQ shuts off. You don't want the delay very long, just long enough to make sure the amp is off before the EQ powers down. Usually 220 - 1000uF is about right. Make sure that the cap is a polarized electrolytic, 16V or higher.

    Regards,
    Chicco

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by Lionel View Post
    The pop is the amp turning on at the same time as your head unit. You mentioned the lines where checked so its not the head unit. With out the line supressor/ filter or cap it can do it every time you turn the head unit on or off. Yes, even while driving.

    What we need to do is delay the amp turn on so its after your head unit or when everything is ready. This will avoid the pop. A line filter, suppressor or capcitor should do the trick. Electronic is best but you have to be very selective.
    Lionel,

    I think I may have confused you??
    The pop does NOT occur when turning the stereo on/off.

    It occurs litterally when you go from NO throttle input to ANY level of throttle input with the engine running, and ONLY when the engine is running. Basically, I would define it as occuring any time the Throttle Position switch is triggered from it's resting point (idle).

    I can lightly tap the throttle pedal while rolling, out of gear and make the pop occur. Same thing when I let OFF the throttle from a constant state.

    Does that make sense?

    -Chris
    Last edited by UNHCLL; 06-15-2009, 04:26 AM.

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  • Lionel
    replied
    We're getting warmer.

    The wiring and RCA's will only help get rid of the noise or whine from the Alt, not the pop.

    The pop is the amp turning on at the same time as your head unit. You mentioned the lines where checked so its not the head unit. With out the line supressor/ filter or cap it can do it every time you turn the head unit on or off. Yes, even while driving.

    What we need to do is delay the amp turn on so its after your head unit or when everything is ready. This will avoid the pop. A line filter, suppressor or capcitor should do the trick. Electronic is best but you have to be very selective.

    Personally never had the need for one but brother Chicco(on this board) understands the inner workings of these items better than I do.

    Shoot him a PM if he doesn't chime in here.

    I also have a source for further help, check your PM.

    L.

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by Lionel View Post
    The ground should be bare metal and to the chasis, the battery terminal is usually the worst place, as you'll get feedback from everything else in the car including the alt (whine). Try and avoid grounding directly to the battery.
    I will try relocating the ground location yet again. I've tried to avoid drilling/screwing new holes into the car to get new ground locations thus far.

    Originally posted by Lionel View Post
    The RCA's are fine(location wise) as long as you don't run them parallel with the battery lead on the right side of the car. The left side is always best for the RCA, remote(1 volt) and your front left speaker when all is amped from the back-forward. The channel under the sill is the best spot to run wire(to me). The tunnel shouldn't be an issue either but never tried that in this car.

    You said you have shielded RCA's thats good as bad one's will allow amplification of the alt noise. thats why most use the twisted cable type RCA's. the twisting of the cable will filter out most noises. Check which do you have and if you have the old black straight wire ones they may be suspect for the whiney noise but not the pop.
    I've swapped RCA's between the twisted, shielded, and old school black straight. No change. I even ran the RCA's out the trunk, through the drivers window, and direct to the headunit. No change.



    Originally posted by Lionel View Post
    1-Grounding, point or size wire. Just so you know the same gauge in as out is a starting point rule of thumb. for most its enough for some it may not be enough if its a bad spot or over 18 inches from your amp. When noise comes in some use a heavier grounding wire to eliminate the problem.
    4 GA in and out. 60A fuse on the positive lead. I've tried running dual ground straps from the amp (2 connection points on the amp) without success.


    Originally posted by Lionel View Post
    2-Everything is starting up cold(Simultaneously as Joe explained)A cap, line isolator or a line supressor will def help eliminate that. As Joe already mentioned.
    This would only cause the "pop" issue on initial startup, correct? I am getting this on every on/off throttle application while driving.

    Originally posted by Lionel View Post
    3-sometimes a bad line from your head unit. This can be checked by changing line ouputs to another line on the head to the amp in question. For say if your sub is acting up and you know the rear channel is fine, use that line to check the sub line. Just don't switch lines while the system is on.
    If I'm understanding this correctly, then I've already done this. I've isolated the RCA's to 1 single set at a time (F, R, S) and still had the same issue.

    Thanks for the help and the link! I'll do some more reading and possibly look into the ground loop isolators.

    If I can't resolve it within the next week or 2 using basic knowledge, I may send the amp back to be tested... or drop it off at a local audio specialist and have them figure it out.


    -Chris

    Leave a comment:


  • UNHCLL
    replied
    Originally posted by UweM3 View Post
    Boston Acoustics GT-40! That's a good quality amp, I am surprised to hear about your problems. Have you contacted Boston Acoustics direct with your problem?
    Everything else in your install is looking fine to me. Long long time ago when I was still into stereo I remember using an inline suppressor, but that was only required with cheap amps.
    I have not contacted BA yet, but may shortly to see if perhaps the power control/processor(?) inside the amp is bad.


    Originally posted by JOEBMW View Post
    I would look into two things....

    Ground Loop Isolators: http://www.radioshack.com/product/in...ductId=2062214

    Also, how do you have the amp remote power ?When does the amp turn on? If you have the amp turn on before the radio sends out a signal (even a 0 zero signal) then you will get noise because the input is floating without the radio on.
    Amp is triggered off the Remote turn on from the headunit directly.
    I have not tried the ground loop isolators.

    I have also discovered that if I turn the audio volume all the way down to zero, I do not get any feedback/pop through the speakers. This has led me to believe that the issue lies with the amps output/power signals, and NOT the wiring to the speakers picking up electrical interference.


    Thanks for the suggestions guys!
    -Chris

    Leave a comment:


  • Lionel
    replied
    With out seeing or hearing its hard to say whats the cause but not impossible, so we'll have to factor out some items.

    The ground should be bare metal and to the chasis, the battery terminal is usually the worst place, as you'll get feedback from everything else in the car including the alt (whine). Try and avoid grounding directly to the battery.

    The RCA's are fine(location wise) as long as you don't run them parallel with the battery lead on the right side of the car. The left side is always best for the RCA, remote(1 volt) and your front left speaker when all is amped from the back-forward. The channel under the sill is the best spot to run wire(to me). The tunnel shouldn't be an issue either but never tried that in this car.

    You said you have shielded RCA's thats good as bad one's will allow amplification of the alt noise. thats why most use the twisted cable type RCA's. the twisting of the cable will filter out most noises. Check which do you have and if you have the old black straight wire ones they may be suspect for the whiney noise but not the pop.

    The Pop can be a few things here.

    1-Grounding, point or size wire. Just so you know the same gauge in as out is a starting point rule of thumb. for most its enough for some it may not be enough if its a bad spot or over 18 inches from your amp. When noise comes in some use a heavier grounding wire to eliminate the problem.

    As an example, I have two 4 gauge wires on each amp, I have 2 amps. I'm tyed to the wheel chok on the left side. It may be bad spot so I used heavier wire. For my buddy's E30 M3 I used single 4 gauge leads from each amp to the rear tower locations and they where enough, there is zero feedback. Also very short distance.

    2-Everything is starting up cold(Simultaneously as Joe explained)A cap, line isolator or a line supressor will def help eliminate that. As Joe already mentioned.

    3-sometimes a bad line from your head unit. This can be checked by changing line ouputs to another line on the head to the amp in question. For say if your sub is acting up and you know the rear channel is fine, use that line to check the sub line. Just don't switch lines while the system is on.

    Hard to pin down to one single thing without being there, but trying to help.

    Also more reading info for you.

    http://www.caraudiobook.com/car_audi...leshooting.htm

    L.

    Leave a comment:

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