Subwoofer not responding to amplifier... Is it blown?

Question

I bought one JBL GT5-10D sub that handles 275W RMS at 2 ohms and a JBL CS300.1 amp (refurbished) that pushes out 300W RMS at 2 ohms. I had them wired and hooked up at a local shop, and they worked perfect and sounded great for 2 days. I had it turned up loud, but not loud enough to cause distortion or even to think about it blowing. But the next day I got in my car, and noticed the subwoofer did not respond to music at all. It would periodically "puff" out and back in (not along with any music). I did not think that it was blown because I thought then it would have still responded to music, but just sound horrible.

I noticed the amplifier lights would blink as it "puffed" out, and according to the manual, this means the amp is not getting enough power and says the amp should be serviced. After a day or two these lights would not even turn on though, which I thought could mean the amp was wired with a bad ground connection.

I took the car back to the shop that did the work and told them I thought I either had a bogus amp or a bad ground connection or problem somewhere else in the wiring, and they said the amp blew a fuse, and said that the sub was also blown. They said I needed a more powerful sub, that it was not a good enough match for the amplifier, even though when installing it they said that they would work perfect together. They then tried to sell me some other subs.

My friends are telling me that they have powered subs with amplifiers that were rated way higher than the subs and they worked fine and never blew, so 25W over should not have done the trick especially since I wasn't pushing it too hard. Even if it did blow, the sub should still be responding to the music, and it should not cause the amp's fuse to blow.

Anyways I am waiting on a 300W RMS sub to arrive in the mail, but I cannot help to think that there is a problem with my amplifier or the local shop screwed up my wiring through a bad ground connection or something since the fuse blew in the amp. Does the washer at the end of the wire that is screwed into the car's frame have to be perfectly flush with the frame? Any ideas?

Thanks

Answer 1

There are so many possibilities... First no the washer doesn't have to be perfectly flush but it must maintain solid contact. If while driving around its moving and losing contact that would be a problem. Second - audio shops will almost always try to hose you. You need to check the power input on the amp, take a simple voltmeter and check voltage, should be less than 12 (you have a 12V car battery). Third did you get a warranty with the amp? if so they will have to fix it. Take your sub out and put it in a friends car real fast see what it does. If it works then its the amp if not vise vera possibly. And turn everything on and take the same voltmeter and measure across the terminals to see what output is going in. You need to check the wattage that you are actually inputting to the sub Power (watts) = volts x amperes. All simple voltmeter readings. Hope this helps but you should make the shop check all this for you in your presence to prove it wasn't them who messed it up.

Answer 2

I'd say you popped the sub. It cannot always be smelt like people think, but it can be small burn on the voice coil itself, causing the sub to sound horrible. I connected a small 15W RMS speaker to a 100W RMS amp once, and it all worked fine until I switched the amp off. Sometimes bad wiring cause the amp to discharge it's current stored energy not at a constant rate, but instantly, pushing out the maximum RMS value in a VERY short time, frying everything that cannot handle at least the power output. I think it's what happened to you, and I'd recommend taking the car back just like that and tell them to fix it. You should get a warranty, and I mean, after just 2 days you really should consider taking it back. They should replace it, just don't take out the sub yourself, it will void the warranty instantly.

Answer 3

that "pop" became better than probably something interior frying, like a capacitor the only thank you to verify is to crack it open and opportunities are high it in simple terms isn't properly certainly worth the money to repair it