Popping sub

[Willard]

Okay, for starters, I have a cheap little aftermarket sub with a built in amp. Has worked fine for me for a few months now. I recently had the back panel off my explorer, where the factory amps are. I finally got around to putting it back on and now the sub pops. Not just with on/off, but pushing any buttons on the HU , and hitting any other buttons in the car (windows, door locks, etc....) will make it pop. When the motor is on it is a constant hum. So, figuring it was the feed wire, I ran a new jumper straight to the battery, same problem. Ground wasn't touched, and worked before, so I think it's fine. Keep in mind the subwoofer works fine, it just pops. I did redo the ends of the phono plugs (one was fubar'd), but it seems this is a power issue, seeing as how it's not just the HU. My next thinking is the remote turn-on. Any thoughts?

 

[Willard]

anybody?

 

[sjr033]

I would first try a new ground. Next I would take my home receiver and run the sub output (rca) into the the amp. If that cures the problem then you know it is in the signal going to the amp, i.e. your head unit. If it doesn't, well you hu is fine. I am not trying to say that your hu is bad, you just to start to eliminate things and that is and easy one to start with. Also if you think it is the remote turn on then you can always run a direct wire to a battery to check that. Let us know if this helps or you need more ideas. Good luck. This is part of installing that I hate the most.

 

[Willard]

Since it worked fine before for awhile, and the only thing changed was the ends on the RCA cable, I might check those out. It just doesn't seem to me that the signal would do it, since it is getting interference from everything. I will also get a better ground and see what happens. Thanks for the input.

 

[Willard]

Well, I redid the ground, same thing, I checked the RCA cable to make sure it was spliced right, its fine. It doesn't do it when I disconnect the input cables, so I guess it is those, but why would my HU do this all the sudden? I think I will try and wire up the high-level input and see if that works.

 

[Infinity08]

Sounds like you pinched/cut a wire somewhere.

 

[sjr033]

You rca's could be picking up a signal from something else. When you ran the rca's are they next to the power wire? What kind of rca's are you using?

 

[Willard]

The rca's don't run with the power wire, so that shouldn't be the issue. I'm just using some cheap ones, but everything worked fine for a few months, it's just when I was back there working on something else they got messed up. I just thought of somewhere where I might have pinched a wire though....hmmm...I'll have to check that out. Is it possible that my HU got messed up from the bad RCA end that was on there before?

 

[The exploder]

Umm, dose it go up and dowen with the engine rev? If you are useing the factory amp i whould check the ground! I had a popping noise comeing out of my door speakers ,and it was a bad factory amp. I had to bypass it ( run all new wires from the deck to the speakers). The other test that you could preform before buying a new amp is try your sub in another car with a amp! If your sub still makes the noise it is problably is blown.

 

[Willard]

Yea I'm kinda hoping that the amp isn't blown, because its a built in kinda and there's no replacing it. Anyways, checked all the wiring, completely eliminated it from the equation. No change. Actually, I didn't check the remote turn-on wire, but I'm thinking that if it works, it's fine. I just don't see how it can cause that bad of interference. I know the sub isn't blown, because it works fine, just whenever you press any buttons it pops. Something is giving it interference. The factory amps are still in service, but they work fine, no noises. I am also thinking if installing a filter in the power line will eliminate this problem.

 

[sjr033]

It IS possible that a bad end messed up you hu. For example you had an exposed wire and it gounded it could cause the output stage of you hu to fry something. Again this is why I recommend you plug the rca's from your home receiver into the amp. To test the hu. I would also try a different set a rca cables. You could spend hours seaching for a kink in your current cables never to fing a kink or a problem with them.

 

[Willard]

I don't have an easy way to hook a home reciever into an amp, but I'll see what I've got and see if I can make something work. Even if the pre-outs are bad I can always just hook up the high-level input and be done with it.

 

[The exploder]

Well then i agree with sjr! He is awsome at audio stuff he walked me through my problem!

 

[sjr033]

You can try the high level input on your amp. I assume you have high level input on you amp? I never liked using them, because you introduce more noice into the system. But for testing, it will work.

 

[Infinity08]

Can you put some shorting plugs into the input of the amp? It is basically an RCA jack with the centerpin shorted to the outside ring. Put a pair of those in and see if teh noise still exists. If so, you have a bad amp and you will have to repair/replace it. You can also temporarily make the short by just jumping a piece of wire.

 

[Willard]

Yes I have the high level input. I think I will try it and see what happens. If it doesn't work, I might try some sort of noise filter and see what happens. I am not sure if those would make a difference, seeing as how the noise doesn't exist without the rca's hooked up. I should also note I have always gotten a little whine from my HU, like interference from the alternator that changed with engine speed, but never did anything about it because it didn't always exist, and wasn't that bad when it did.

 

[Infinity08]

Yes I have the high level input. I think I will try it and see what happens. If it doesn't work, I might try some sort of noise filter and see what happens. I am not sure if those would make a difference, seeing as how the noise doesn't exist without the rca's hooked up.

But we need to determine which "end" of the RCA's is inducing the noise. That's what my test above will find. Is it a factory head unit, or a Pioneer by any chance?

 

[Willard]

Nope, neither, it is an aftermarket Dual head unit.

 

[Infinity08]

I know that on some Pioneers there's been problems with people blowing tiny fuses in the heads that allow noise like you describe. It's entirely possible the DUal works the same way, but I'd want to be sure the noise comes from there as opposed to the input section of the amplifier. This thread MAY be helpful if it's the same thing. I haven't read it all since I didn't have any issues (or even a Pioneer deck).
http://www.diymobileaudio.com/forum/showthread.php?t=13889&highlight=Pioneer+noise

 

[Willard]

hmmm....very interesting. thanks for that link, i might have to look into that.