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Unread 08-16-2010, 08:15 PM   #1
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Default Amp died?

So, I was driving listening to some dubstep (driving the sub like i've never done before) it wasn't really loud, it had a good rumble though. All of a sudden the bass died. I turned the car off and looked at the amp, it was hot.. very hot to touch. I let it cool down and turned it back on, no bass coming at all. The amp lights up and it's cooled down now but no bass. I checked my h/u wiring, tried regrounding in a new position. Checked the controls on the amp&h/u, checked the fuses, I don't know what else to think other than the amp is toast or something. Anyone provide insight?

JBL bp300.1 amp, 12" rockford fosgate punch and a sony cdx gt240 h/u.

Thanks

Last edited by chevymeister; 08-17-2010 at 02:40 PM.

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Unread 08-16-2010, 10:36 PM   #2
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Troubleshoot the driver, too. Touch a 9-volt battery to the input terminals, and the cone should 'pop' either in or out and stay there. If this procedure produces no cone movement, you've got an open circuit in the driver, almost certainly from a cooked voice coil.

Modern amps get hot, but usually shut themselves down before component damage occurs. Loudspeakers are not quite that smart - and the extended sine-wave like content found in music like dubstep is brutally difficult on a speaker.
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Unread 08-16-2010, 11:31 PM   #3
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I second that it sounds more like a fried voice coil. Though that is a good speaker brand, I am not sure on your models exact details. That amp should have a thermal shutdown where the power lamp turns from green to red when it goes into protection mode.

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Unread 08-17-2010, 01:08 AM   #4
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I seen a green light when I turned my car on recently, if it isn't in thermal protection mode is should work right?... I took apart the amp + sub enclosure. All the solder joints are solid and working. I even crimped most of the wires in my head unit and redid it all (was electrical taped before :P). Bah, if it's a voice coil, what should I do to fix/prevent this from happening again? It'd suck if I have to buy a new amp... costs me a fortune for having to pay tuition lol.

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Unread 08-17-2010, 12:33 PM   #5
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They're talking about the sub. Your amp and wiring are most likely fine, it's a mechanical issue. Try what Chip said with the battery first.

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Unread 08-17-2010, 12:37 PM   #6
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If you want to prevent it always make sure your amp's peak wattage is equal to or slightly less than the speaker's RMS wattage. No way you can blow a speaker that way.
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Unread 08-17-2010, 12:41 PM   #7
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Quote:
Originally Posted by Kenny McCormick View Post
If you want to prevent it always make sure your amp's peak wattage is equal to or slightly less than the speaker's RMS wattage. No way you can blow a speaker that way.
How exactly can I set that? :S (i'm retarded with car audio, i'm still learning )

I have a bass boost, lpf knob and input knob on the amp, that's about it.

I'll try what chipp said, does the wires from the engine/deck and that have to be in the amp to make this work? I took it all apart, (and i'm assuming the 9 volt touches the 2 terminals that are on the outside of the sub enclosure)

Last edited by chevymeister; 08-17-2010 at 12:45 PM.

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Unread 08-17-2010, 01:30 PM   #8
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Quote:
Originally Posted by chevymeister View Post
How exactly can I set that? :S (i'm retarded with car audio, i'm still learning )

Pay attention to specs when you buy new gear to replace what you broke.

Example: I don't want a huge system in my Ford(I listen to rock, so I want the whole song not just the bassline), so I'll end up with a sub that does around 300W RMS, tops. I would get an amp that can do 300W peak, that way I'd never have to worry about blowing a speaker. Maybe a 350W if I'm feeling lucky.
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Unread 08-17-2010, 01:48 PM   #9
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Well I have a 12" punch 2 sub @ 250 Watts RMS

The bp300.1 jbl @ 300 watts RMS x 1 channel at 2 ohms


So I believe I set the impedance right, the positive on the far end of the amp and the negative on the other far side of the amp.



Also I checked my amps manual online and turns out green light + no audio can indicate an overheat. Is it still possible? I just showered so i'll test the 9v thinger now.

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Unread 08-17-2010, 02:00 PM   #10
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Quote:
Originally Posted by chevymeister View Post
How exactly can I set that? :S (i'm retarded with car audio, i'm still learning )

I have a bass boost, lpf knob and input knob on the amp, that's about it.

I'll try what chipp said, does the wires from the engine/deck and that have to be in the amp to make this work? I took it all apart, (and i'm assuming the 9 volt touches the 2 terminals that are on the outside of the sub enclosure)
Nope, you don't want anything else connected at all. Just the bare driver, or the input terminals on the cabinet.
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