Rep Power: 388

ok I have the annoying thump from my subwoofer amp when I turn on my car or shut it off etc.
here is the current configuration
I used the Kicker 0 gauge Flex cable which made my install very easy

JL Audio 500/1 , JLaudio 300/4
0 gauge >150amp fuse to power distro block in the back
0 gague ground distro block in the back

No alternator wine, no voltage from the remote lead when changeing stations , power on etc.

Streetwires Zero Noise 2 RCA Patch cables <=---- here is where I found something unusual I have a voltage drop to almost zero when I power on, change stations , switch to cd/dvd on my headunit.



so what is my thought on this? I beleive I have a malfunctioning brain for my clarion vrx935vd headunit but is that anyone else that has ran into this or can think of something else to test?

 
Rep Power: 388

no one have any ideas to help out here? I am basically having a signal lose on my no fad out or better known as subwoofer channel

 
Rep Power: 0

Here are a couple of threads from a different board that deal with the same thing.

The first one has some good information to try but some of the guys get pretty far off topic, which you will have to sift through. The problem ended up being the amp.

http://forum.elitecaraudio.com/showt...hreadid=115815
http://forum.elitecaraudio.com/showt...hreadid=113040
http://forum.elitecaraudio.com/showt...hreadid=100095


Hopefully this can ofer a bit of help

 
Rep Power: 336

When you turn off or turn on the car, it will supply/kill power to the amp and HU..along it will supply the ignition(accessery mode)

I bet you when you turn off the HU first and turn off the car it will NOT pop..
the links James77 mentioned uses this method to isloate the problem....the third link also tells that some tried to put small capacitor and a diode to solve the problem....the first link on second page tells that he won't get pop when he turns off the HU first and turn off the car...

The problem is this...when you turn off the car, the battery will shut off battery power to all electrical systems(I.C.E) and they will shut off...then the race condition occurs

In engineering term,race condition is...the amp and the HU is going to lose power when you turn off, but HU turns off first...and that is a problem...for that brief time the amp is still turned on....but the HU is dead and that abrupt change in the audio signal is fed into the amp making that pop...its really the design of the power supply and remote turn on...

above links have very good solutions to this....

 
Rep Power: 388

Thanks I have considered this but i'm not wanting to install a filter or something that seems to be related to my brain for my Head unit


I already understand how amps , power , ground etc work and the links are a help yet here is what i've done and ruled out where my problem is

Tested my new rca cables ( Streetwires zero noise 2) they are 100 % ok with a DMM

Remote Lead turn on is 100 % ok when tested it does not change voltage or anything when changeing stations or changing function from radio to cd/dvd etc

I also changed my remote lead to signal sense instead because the JL amps offer that ability and still recieved the thump

I also tried a constant on power source which ended in a thump again

I however did find that I have a voltage drop on my signal from my sub output to the amp when I change stations and functions which has lead me to beleive I have a faulty Brain subwoofer output on my headunit.

 
Rep Power: 336

So you know the cables are good and they are not the problem...also you are getting constant power...rule that out too...so its down to AMP or HU..

about switching stations and functions radio to cd etc, HU is designed to mute the output for a brief time to allow changes in the signal...that time is in fraction of a second thus making no difference in human ears...

First thing I would do is ...Did you get a chance to turn off the HU first and turn off the car....observe Pop or no Pop?
Second thing would be to change the amp if you have another brand.....this is the best method to rule out amp...

let me know what the outcome is....

 
Rep Power: 388

i'm goign to test this later tonight but I do not get the same result on my other amp thats feeding my front components and rears, both amps are JL audio and moved from my civic to my dc5

 
Rep Power: 0

I would try testing the amp too. Try hooking the subs up to the 300/4 with the sub RCA. If it still makes a thump you know its the H/U. Otherwise its the amp.

 
Rep Power: 388

ok I ruled everything out down to what I suspected it is the braind off of my Headunit that has a problem with the sub output on it. I have to pull out my HU and the brain to send back to clarion now damn it

 
Rep Power: 336

cool.....I will lend you my portable radio for you to listen