getting a thump when amp turns off

[csu87 10+ year member]

so i installed a new amp today and after i was done, i noticed that everytime my hu turns off, my amp thumps loudly. I used the same power, rca, rem. wires from my old amp. the only thing i changed is my ground, which is about 4ft now instead of 2.5ft like before.

I know it is usually a ground issue so i tried a couple different places and it still thumps.

its wierd because my old amp never did, and i pretty much just unplugged everything from my jbl and put it in my planet audio.

what do you guys think could be the problem.

CLIFFS: didnt have a thump before but now i do

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[grimreper912003 5,000+ posts]

Some amps are built with a filter that stops it, some arnt. You could try grounding your RCA's, or possibly check the connection of the ground at the amp.

 

[KyleBechtold 5,000+ posts]

you sand the ground down all the way?

 

[csu87 10+ year member]

you sand the ground down all the way?

yep. i also tried about 4 different places. and each time it was the same

 

[shakinghorizons]

Could be the amp i had a friend that bought a planet audio amp and had to return it, everytime you pause it, it would sound like a tunnel. The amp would echo the bass once it had stopped playing a note on pause, for a good 2 seconds.

 

[csu87 10+ year member]

Could be the amp i had a friend that bought a planet audio amp and had to return it, everytime you pause it, it would sound like a tunnel. The amp would echo the bass once it had stopped playing a note on pause, for a good 2 seconds.

mine doesnt do that. it sounds great except for the thump. I had heard somewhere that there is something you can buy, like a relay switch or something, but i cant find where i saw that.

i have an extra pair of rca's so ill try them and see if it helps.

How do you ground the rca's?

 

[shakinghorizons]

Touch the outer jacket of the RCA to ground while turning your headunit off and see if i works. Also i hear you aren't supposed to have power to your HU when you plug in the RCA's. Some tiny filter or something can blow and cause loud thumping. Did you have it unplugged?

 

[csu87 10+ year member]

Touch the outer jacket of the RCA to ground while turning your headunit off and see if i works. Also i hear you aren't supposed to have power to your HU when you plug in the RCA's. Some tiny filter or something can blow and cause loud thumping. Did you have it unplugged?

i had the batt disconnected. so no power to the hu.

 

[shakinghorizons]

Did you mount the amp next to your magnets?

 

[csu87 10+ year member]

its on an amp rack towards the top of the box. filled with foam and has some dynamat inside. heres a pic. i dont think there would be any magnetic interference.

 

[AlterEgo99 5,000+ posts]

mine doesnt do that. it sounds great except for the thump. I had heard somewhere that there is something you can buy, like a relay switch or something, but i cant find where i saw that.

You may be thinking about connecting the remote on to a relay, which is what I do. Here is the link: http://www.bcae1.com/

On the right side of the page, scroll down to "Relays", it's topic #36.

I'm not 100% sure that this will solve you issue, as it sounds like it may be the amp itself, but it is a pretty cheap and easy solution to try.

 

[pawn man 10+ year member]

sounds like you either have a grounding problem or the gains on the amp too high.

 

[csu87 10+ year member]

the gain was set below rms capabilities with a dmm so i dont think its that. do you think 4ft is too long for a ground wire from the amp? ive always had them 1-2.5ft and havent noticed thumping

 

[alex95sl2 10+ year member]

i have the same problem with my fusion so ima be watching this thread for solution

 

[csu87 10+ year member]

so i found out that if i turn off the amp before turning off the hu it doesnt thump. but, when the amp is off and the hu turns off it still thumps, so i think it might be something w/ the hu. ill take it out after work and see if any wires came loose or if a fuse or something blew in my hu