signs of defective amp????

DJamesUofM · Post by **DJamesUofM** » Sun Sep 26, 2010 3:58 pm

I have had my audio in my car for well over a month with no problems. my battery died on Friday, and had to buy a brand new one. Last night while I was driving, all of a sudden my front headlights flashed on and off once really quick, and my Subs stopped playing. I decided to wait till today to try and work on it, and come to find out BOTH of the 30 amp fuses on my amplifier had blown. I checked all the grounds and the wiring to see if maybe something had shorted it out. I tried many things and tried putting new fuses in as I want, but got the same result every single time. My car would be completely off, but as soon as I would touch the fuse to the connectors the fuse would either blow instantly or begin to melt and then blow. I am 150% sure that there is no short in any of my wires, and the only other conclusion I can come up with is that my amplifier has something wrong internally. I have yet to attempt to try another amplifier with the same wires, so it is still a POSSIBILITY that it could be the wires, but I doubt it. Can anyone give me some insight on a possible problem? And how to fix it, if possible?

Just so anyone that reads this knows I own a PR500.1 Memphis amplifier its about 3 years old. And the subs are not wired to 1 ohm, they are wired for 2 ohm.

Post by **ttocs** » Sun Sep 26, 2010 5:53 pm

did you jumpstart your car when the battery died?

DJamesUofM · Post by **DJamesUofM** » Sun Sep 26, 2010 6:21 pm

i sure did, why?

gridracer · Post by **gridracer** » Sun Sep 26, 2010 9:30 pm

Does your main power wire have a grommet where it goes through the firewall?

DJamesUofM · Post by **DJamesUofM** » Sun Sep 26, 2010 9:59 pm

yes it does go through a grommet

Kurt Wild · Post by **Kurt Wild** » Sun Sep 26, 2010 11:01 pm

If the amp fuses blow, the fault _can not_ be in the wires. Your amp is internally shorted.

DJamesUofM · Post by **DJamesUofM** » Sun Sep 26, 2010 11:12 pm

@Kurt Wild...if i take the amp apart is there any possibility that i could find the problem? and it would appear you are saying that a short in the wires wouldn't cause my fuses to blow and i find that hard to believe.

Kurt Wild · Post by **Kurt Wild** » Mon Sep 27, 2010 12:55 am

If your power wire shorts to the car chassis then it will blow the fuse near the battery. The amp fuse only blows if your amp draws more current than its designed for. This will happen if you overload the amplifier or something goes wrong with it.

Inside the amp you will probably find dead (shorted) power transistors.

Post by **ttocs** » Mon Sep 27, 2010 4:34 am

alright you jumpstarted your car, what size power wires are you running t your amp and have you upgraded your stock power wires? Reason being if you are running thicker/better power wires then the stock power wires, I suspect when you jumpstarted your car the heavy current needed to start it followed the path of least resistance which would have been your amplifiers upgraded power wires which led it through your amp. This is why it blew the fuse, and unfortunatly probably a FET or two....

that is my guess.

Kurt Wild · Post by **Kurt Wild** » Mon Sep 27, 2010 4:52 am

A lot of guesswork going on here..

When jumpstarting a car an external power source is connected directly to the car battery, right? There is no way i can think of the starting current going through an amplifier.

Only way these incidents could be related is some sort of power surge occurring at jumpstart and injuring amp.

Simplest explanation is that the amp just died. (Sh) It happens.

Post by **stipud** » Mon Sep 27, 2010 6:41 am

Something would have to be shorting out in the power supply section of the amplifier for that to occur without the car turned on. It could be as simple as a stray wire across two leads inside the amp, or it could be a massive failure. Hard to say really.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 7:07 am

i'm pretty sure the power wire is 4 gauge (or better)...so it could be possible that jumpstarting my car caused something in the amp to fail but the failure didn't occur until a few days later after i had been running my amp and subs for a while. SOOOO more than likely i need to get a new sub?

Post by **stipud** » Mon Sep 27, 2010 7:23 am

DJamesUofM wrote:i'm pretty sure the power wire is 4 gauge (or better)...so it could be possible that jumpstarting my car caused something in the amp to fail but the failure didn't occur until a few days later after i had been running my amp and subs for a while. SOOOO more than likely i need to get a new sub?

The only way it would be the sub is if it has completely shorted itself out. If you disconnect the sub, RCAs, etc from the amp and just leave the power inputs and it still blows fuses, then odds are it is FUBAR.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 7:55 am

FUBAR?

ReneBMW · Post by **ReneBMW** » Mon Sep 27, 2010 8:15 am

Fucked Up Beyond All Recognition

Post by **Eric D** » Mon Sep 27, 2010 9:53 am

Jump starting a car won't kill an amp, unless you did something majorly wrong when you jump started it.

Post by **ttocs** » Mon Sep 27, 2010 10:31 am

I agree it shouldn't, but where did you ground the jumpers on the battery or on the chassis? It was purely a guess but it could happen if he grounded the cables to a bad location. The 4 awg wire you ran is obviously much thicker then the stock wires, I have no other guesses as it is hard for us to say what did or did not happen from this end of my monitor.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 10:42 am

went to an audio store out here and told them exactly what was going on. Said the PSU is proly fried. That was before I told him that I jump started my car. when I told him that he asked if I took at the power wire fuse. told him no, and he basically told me thats what caused the issue right there. He said they still aren't rele sure how jump starting the car causes adverse effects on the amp but they know that it can.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 10:42 am

Already found a new amp to suit my needs (:
http://www.sonicelectronix.com/item_230 ... gn=froogle

apparently i misread the specs and thought that it put out 600 RMS at 2 ohms...nevermind on this amp. seems like there aren't many subs that will put out 600 RMS at 2 ohms. my alpine type S's are only rated to be able to handle 300 RMS and i have 2 of them, i'm sure the answer to this question will be yes, but will the subs be able to handle an amp that puts out 650 RMS at 2 ohms essentially both subs are getting 325 watts each? i've heard so many times that the numbers that the manufactures put out are more there so that people don't just go blowing the subs left and right. And 25 watts seems minimal to me.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 10:44 am

and relating to an earlier post i mean "get a new amp" not "get a new sub"

Post by **ttocs** » Mon Sep 27, 2010 11:14 am

well I would measure the woofer with a meter to ensure it is still good but it should be.

I have seen this every once and a while when I was working at a shop. It shouldn't happen but it does occasionally. If I were you, I would upgrade your stock wiring to match your amp wires, or at the least disconnect all the ground connections on the battery and clean them to make sure it is still good. I have heard all kinds of theory's, but the only one that ever made sence to me was that corrosion might have developed somewhere in your stock connections to where it is less resistance to seek the ground through the amps power wires, meaning through the amp as well...

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 11:22 am

well a little while after i bought the car i decided to take a look at the battery and the positive terminal was the most corroded i had ever seen a terminal get to. i mean it was just a mound of corrosion, you couldn't see the terminals or anything. So this could have had an effect on it.

and i already measured to make sure they still work and they should...gonna try them on a friends amp eventually to make sure before i buy a new amp.

Post by **ttocs** » Mon Sep 27, 2010 12:10 pm

that could possibly make sence. It will take the path of least resistance so it is possible that your new cables with the amp posed less resistance then your corroded factory cables to power the starter. I have some scosche platinum battery terminals that have been in the free section of the classifieds for a little while now. Cover shipping and any fees and you can upgrade them if you want. There has also been some 4 awg in bulk I think that you could match up with some fuse holders to upgrade your big 3 cables since you are going to pay some attention to hit. Do it right and do it once and you don't have to mess with it.

DJamesUofM · Post by **DJamesUofM** » Mon Sep 27, 2010 2:39 pm

i just rele dislike doing things under my hood cuz my engine bay is so compacted together.

gridracer · Post by **gridracer** » Mon Sep 27, 2010 3:17 pm

Please do not buy anything soundstorm it WILL fail.