Is my sub knackered?

[Loz]

I have just put my sub back in aftermy traumatic incident on the M62 whereby I had to remove it from my car with a pair of tweezers about a month and a half ago. Popped it back in, reconnected all the wires and it works, but it just isn't right. It's constantly rumbling even when it has no beat or noise to produce from the song and it seems to sort of reverberate when it makes a beat. Also, it pops pretty badly now when I turn the engine off and my stereo goes off. It had always done it quietly to a degree but is now much worse. I'm no expert so I don't know what is causing this. Maybe I damaged the wires by tugging at them when trying to remove them with no screwdriver? But I'd have thought it just wouldn't work altogether if that was the case. I was wondering if maybe the speaker has got knocked and damaged or something. Just wondered if anyone had any ideas? I don't really want to have to go and spend another £200 on a new one

[cheezemonkhai]

Check all the connections, especially the ground

[4x4t]

Sounds like an earthing problem to me.Check the earthing point you could even try putting another cable from the amp to another earthing point to see if it cures it.If it has a built in amp there could be a dry joint on the circuit board.

[woodenspatulas]

sounds like a dodgy earth, or maybe may even the amps got a problem. check all wires to make sure its no a bad wire. does the noise stop when the engine is turned off? or does it do it all the time (the rumble i mean)

[Loz]

As soon as it's turned off it's silent, but all through songs it sort of rumbles. I'll look at wires, but they were all in the amp fine. Bit of a bugger

[cheezemonkhai]

It sounds like when you took the cables off one of the connectors (A crimp type maybe) has worked itself a bit lose on the wire.

From what you have just there it sounds very much like a ground fault. Good luck finding it and if you don't have any luck it might be worth paying a car audio place £40 to fic the damaged connection and put a suitable connector in to make it easier ot remove without tools next time.

HTH

[stuart_hatch]

Check your crossover on the amp, sounds like it might of been turned all the way up (hense the rumbling)

(and seemly this message is too short, so the forum is telling me to add words :S )

[smstext]

you didnt rewire it anywhere on the line and have you made sure the positive goes to positive and negitive goes to negative too?

[Shifty]

Im guessing your earth point is in the boot, you may have dislodged where its connected. Pop it round i'll have a look.

[Loz]

Thanks guys.

It's entirely possible that I have damaged a wire and I was pulling very hard on them just to gtet them off the amp. I didn't care if I damagaed them, I figured that could be sorted another time! They didn't come off though and didn't appear damaged. Not really sure how to tell?

My earth wire is bolted to my boot catch. It's still there, bolted firmly. I was only pulling on the amp end so any damage would probably be there. I have a new earth wire that needed putting in anyway.

[smstext]

unless youve blown a capacitor in the amp????

[KenONeill]

If the sub was off when you disconnected it, I'm pretty sure it's a connector or a reversed wire. If it was on, it may be a capacitor or a screening issue.

[Loz]

I don't know what capacitors are?

[KenONeill]

A capacitor is a piece of electronics that stores current for short periods. One of their functions is to suppress electrical noise from things like electric motors, and your sub's just above the fuel pump.

[Loz]

Right ok, so how do I test all these theories then? I don't know where to start

[cheezemonkhai]

First thing to do Loz is to check all the wires are connected the right way, eg +ve to +ve on the amp and sub.

Next change your earth wire for the new one you have as this is a very likely cause of noise.
(It is also worth checking there is a good contact where it meets the bodywork as paint can cause prolems here).

I would seriously doubt you have damaged any caps and they are internal to the amp so there is no way to check these short of taking the amp apart.

If you do find out that a cap is leaking then they can be changed for pennies.

If you can't find somebody up there to do it for you then I have a gas soldering iron and can order the parts from somebody at work, so could probably do it at a meet.

Out of interest with the sub in the boot and the fuel pump under the rear seats I would say the chance of interference from that is small as otherwise it would affect the unshielded cables to other devices too.

[cheezemonkhai]

Also you might want to try gently pulling side to side on the wire while holding the connector (I do mean gently) and if you think the wire is moving either get a new one or get somebody to put a drop of solder in it or crimp a new one on.

Hope that Helps

[KenONeill]

(but can't help). I tend to not explain stuff to you until you ask Loz, because I know you're bright and well edumicated, and I don't want to insult your intelligence!

[Loz]

ok cheers. They are connected right on the amp, I did twiddle with them a bit to test for connections and stuff. I have unplugged the line in line out for now as I cant be doing with listening to it. I will get the new earth cable put on and see if that makes a difference......

[Loz]

Ok, earth wire changed, problem not resolved What can I do??