white noise coming from subs?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112185
Printed Date: April 29, 2024 at 2:10 AM
Topic: white noise coming from subs?
Posted By: trae08
Subject: white noise coming from subs?
Date Posted: March 07, 2009 at 5:53 PM
Ok well i don't have any pictures saved on my computer but if they will help theirs a few pictures of the stereo equipment on this site.
https://www.cardomain.com/ride/2621467
Anyway in my step dads car there is a hissing / white noise type noise coming from the sub box, not sure from which sub its coming from exactly but Ive tried everything i can think of without opening the box. Its not alternator whine and i am out of ideas, The noise stays the same volume no matter how loud the music is so if you turn up the volume you cant here it. And i unplugged the sub pre amp outputs and it still made the same noise. Not sure if it is coming from one sub or all four. Depending on what you guys say i was gonna unhook all the subs from the amps and hook up 1 at a time to see if its all four or just one.
Replies:
Posted By: trae08
Date Posted: March 07, 2009 at 5:55 PM
sorry, make model of vehicle is 2006 hummer 2 and all the stereo stuff was installed in 2006 so it was probably manufactured in 2005.
Posted By: haemphyst
Date Posted: March 07, 2009 at 7:23 PM
ALL amplifiers will hiss. If it is very low level, like so low that you have to put your ear right to the speaker (or close to it, even up to a foot or so away) to hear it, that's perfectly normal. Don't worry ablout it.
-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: i am an idiot
Date Posted: March 07, 2009 at 8:01 PM
And to add to Haem's statement. There is no way that it is a woofer making the noise. It has to be the amp. if it is a multiple channel amp, the noise may be coming from only one woofer, but the woofer is not capable of making the noise.
Posted By: trae08
Date Posted: March 08, 2009 at 9:55 AM
Well it only started doing it around December 08. And when you say the amps are making that noise you mean the amps themselves or the amps are causing the subs to make the noise? Cause Ive checked all the wiring on the amps while it was running and they were not making any noise.
Also its not quite enough for me to put my ear to the sub to hear, i can hear it from the driver seat and even standing outside the vehicle.
If its normal then why would it have only started doing it last year when we've had it sense o06
Posted By: DYohn
Date Posted: March 08, 2009 at 10:12 AM
Sounds to me like either the amp or HU is defective, or you have developed a ground loop. Make sure your ground return resistance is good first. ------------- Support the12volt.com
Posted By: haemphyst
Date Posted: March 08, 2009 at 6:29 PM
Describe the noise. Is it a constant, unchanging hissssssss, or is it a buzz that changes pitch with engine RPMs? A hiss, if it's that loud, and is present with all inputs diconnected, would indicate to me that the amplifier is bad, and needs repair or replacement.
The "new" changing buzz with or without RCA cables connected, would be an installation issue.
Whichever it is, I am sure that we can't help you without a correct description of the noise first, which we do not have.
-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: i am an idiot
Date Posted: March 08, 2009 at 7:05 PM
Is there a gain control on the amplifier? Have you tried turning it down all the way to see if the noise goes away?
Posted By: trae08
Date Posted: March 14, 2009 at 7:44 PM
Alright well unfortunately the problem wasn't nothing anyone suggested. i unhooked both subs from the top amp and noticed the noise went away which told me the problem was with the top amp, So i unmounted the amp and took the top cover off as i was doing that i heard something on the inside which sounded like a screw or something that came unscrewed but turns out it was this.
1st picture is the busted mosfet
2nd picture is the piece that busted off
3rd is the entire amp without the cover plate
I have another question, i know this is repairable but what is the average cost for something like this?
Posted By: haemphyst
Date Posted: March 14, 2009 at 9:39 PM
Well, SOMETHING took that device out. I bet cash it's not going to be as simple as just replacing the device.
How much? Who knows...
-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: trae08
Date Posted: March 14, 2009 at 10:09 PM
So you mean there was another problem that caused the mosfet to bust?
Under normal circumstances and being 3 years old what would cause something like this?
Also the amp still puts out perfect bass but should i just unhook it from the power source anyway to prevent damage to the subs?
Posted By: i am an idiot
Date Posted: March 14, 2009 at 10:24 PM
I know. Do you have an ohm meter? All of the output devices that are directly connected to the exploded one need to be replaced. With the meter we can determine how many of them are shorted. Once we find that out, we can cut the shorted ones from the equation and see if the amp will play properly with the remaining transistors. The only thing this will do is let us know if there are other problems, or just the shorted outputs. Once we cut the shorted devices out, you need to reinstall it and see if the noise is still there. If you have a meter and want to check it out so I can let you know what you are looking at to get it repaired. Are the number on the FETs IRFP3415? Did the metal screen mounted to the inside of the plastic in the center of the amp fall into the amp? You are probably looking at a 250 dollar repair. (Assuming the other 8 outputs are OK) Those transistors are soldered to those strips. DO NOT TRY AND REMOVE THEM WITH PLIERS. You must use a torch.
Posted By: trae08
Date Posted: March 14, 2009 at 11:30 PM
Alright here we go, i know how to take things apart but have no idea what most of the stuff inside is, so yes i have an ohm meter, what do you mean by output devices? and what do you mean by cut them out?
and also are the numbers important? cause i already put everything back together, if you have to have them i can get em though.
you mean the screen on the inside of the top cover right? no that was still attached to the cover,
wasn't going to try and remove anything. but thanks for the tip. and all the help
|
