so i just installed a system in my girlfriends car and now when the radio shuts off the subs like recieve a surge of power maybe and they bump one hit and shut off?? bad rcas? whats going on here? any help pls

 

What type of HU and amp? If its a loud thump its probably the amp shutting off, cheaper amps typically do not have a turn-off/on delay. I would also check the RCA's and ground, just to make sure.

 

its an alpine hu, and its an orion amp. its the west coast customs subs and amp preassembled setup. i have the rcas wired red to red white to white on both the hu and amp. when this was installed in my car i dont remember it ever hitting when shutting off. the ground is grounded out to the body of the car and run to the capacitor, and then from the cap to the amp.

 

It happens. Sometimes the delay stops working properly in the headunit or amp and you get this. It's not a huge deal besides being a little annoying. You can make your own delay, but if it's something you can live with I wouldn't worry about it too much. Where did you attach the remote wire for the amp? Did you hook it to the remote output of the headunit, or to just the acc. wire?

 

remote wire is connected to the amp where it should be and runs to the remote wire coming out of the hu harness. i bought her a new sub setup and new amp n when those come in if the problem is still the same then my guess its the rcas but for now i guess she will have to deal with it

 

Shouldn't be the RCA's themselves. What causes that problem is the signal coming from the RCA's is cut before the amplifier's power has shut off. When the signal is taken away from the inputs, the amp, amplifies that disconnection andyou get that "Thump". The same thing can happen when the amp turns on if the amplifiers power turns on before the signal from the RCA's is present. That's why most amps take a second to turn on, then you get that little "click" and then you get sound.

 

Some headunits have a SSC (Soft-Start Cicuit) in them too, that can malfunction and cause a thump too.

 

so theres really nothing i can do about this thump then? the headunit is only 3 days old now so im sure its not that. thanks for the info i guess ill just have to deal with it, or she will as long as its not damaging the subs or anything?

 

Yeah pretty much, or change the amplifier. Like I said you can build a circuit that will basically cut either input, or output (to the speakers/subs) until the amp has fully turned on/off, but it's pretty involved and you usually get a humming or buzzing instead of the thump. So it's a little pointless. It shouldn't damage the subs. Unless it is over extending them (Bottoming out) when it does it, it will not damage them.

 

well the new amp and subs came in, i checked the rcas, they were bottoming out behind the hu because its so crammed back there, also the hu ground wire came undone. redid the wire, taped off around the rcas and no more thump, then hooked up the new system and its working like a charm