strange turn off thump

[SiCkNaStY24]

I recently had a turn off thump start occuring the other day in my car. Every time I shut my car off my sub will hit once. Also every time i unplug the usb cable for my ipod from my head unit it will thump aswell. It only does it at those times aswell. Ive had this setup for a year now and it just started to happen a few days ago. I have not changed anything either which is the strange part of it. Please help me fix this very annoying issue!! i have checked all wiring for the HU and ran a new remote wire and rca wires and that didnt help this issue either.

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[DeathByWaffle 10+ year member]

Does it happen when your volume is turned up or when its set at 0?

 

[All_Logix 10+ year member]

Sounds like you have some residual charge somewhere that is being fed into the sub...could be the HU itself for some reason sending signal through the RCA when this happens, try running rca to like an ipod or something, turning the car off and see if you get the same result...if you do, the HU is out, then I would guess the amp, maybe for some reason the voltage on your speaker outputs are spiking... Kinda hard to really diagnose over the internet

 

[SiCkNaStY24]

what do you mean try runing the rca to an ipod? I am thinking its the amp itself causing it. Its about 3 years old now if that matters

 

[maylar 10+ year member]

Most likely HU related. You can rule out the amp by removing the remote wire while the system is powered up. If no thump, it's the HU.

Dunno about the "removing USB cable" thump though.

Lots of Google hits on turn off thump.. here's a link you might wanna read..

One more turn off thump thread - CARSOUND.COM Forum

 

[Bumpin' Goalie 10+ year member]

Most likely HU related. You can rule out the amp by removing the remote wire while the system is powered up. If no thump, it's the HU.
Dunno about the "removing USB cable" thump though.

Lots of Google hits on turn off thump.. here's a link you might wanna read..

One more turn off thump thread - CARSOUND.COM Forum

Many head units, when the iPod is unplugged, will go into Standby (or similar) and thus turn off external amps. To me, sounds like there could be a ground issue at play somewhere or there is unnecessary signal being sent at turn on.

 

[ChevyRidinLow]

ground and shield the rcas, re ground the amp, if you have a capacitor throw it the **** away and retune the amp/headunit output settings.

 

[SiCkNaStY24]

So I swaped out my amp with a old one i had laying around and there is no thump at all. So it has to be my planet audio amp causing the problems.

 

[bubbagumper6 5,000+ posts]

Amplifiers have built in circuitry to prevent turn on/off thumps but that circuitry is just resistors and capacitors which CAN and DO fail...it could be as simple as a faulty cap in the amp starting to go bad.

 

[Vossy 10+ year member]

Likely the HU, my buds SAZ and SA's do it.

 

[bubbagumper6 5,000+ posts]

Likely the HU, my buds SAZ and SA's do it.

He said he swapped out the amp and it stopped...not the HU