Sub "thump" when car is turned off

[Sleeklsc 5,000+ posts]

So im running my factory jbl system(comps front/rear,ext amp) with a pa 2400db and 2 12" type r's..I used a pac line out converter and installed it correctly. The problem is whenever i turn off the car it makes a thumping noise(subs). It only lasts 1/4 second but is sort of annoying but i've gotten used to it...If i just turn off the factory cd player it wont "thump".

The amp and loc are grounded to the frame so that cant be the problem.

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[BigSix 10+ year member]

gains probably not matched

 

[BigSix 10+ year member]

So im running my factory jbl system(comps front/rear,ext amp) with a pa 2400db and 2 12" type r's..I used a pac line out converter and installed it correctly. The problem is whenever i turn off the car it makes a thumping noise(subs). It only lasts 1/4 second but is sort of annoying but i've gotten used to it...If i just turn off the factory cd player it wont "thump".The amp and loc are grounded to the frame so that cant be the problem.

where do you have your gain set up at?

 

[The HACKER 10+ year member]

try grounding your RCA's sounds like they are picking up noise from somewhere and unloading it when you turn off car. Mine used to do that as well.

 

[Sleeklsc 5,000+ posts]

where do you have your gain set up at?

Alittle less then half

 

[Sleeklsc 5,000+ posts]

try grounding your RCA's sounds like they are picking up noise from somewhere and unloading it when you turn off car. Mine used to do that as well.

Do you mean the rca's from the loc to the amp?

 

[The HACKER 10+ year member]

Do you mean the rca's from the loc to the amp?

Well what you could do is hook up a DMM to the rca's and see if you get a voltage spike when u turn the car off //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif to see if thats ur problem.

 

[hatedonmostly 5,000+ posts]

Definitely a ground loop issue.