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Sub and Amp Matching - Blown Fuse

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=44197
Printed Date: May 16, 2024 at 2:11 AM


Topic: Sub and Amp Matching - Blown Fuse

Posted By: dxav
Subject: Sub and Amp Matching - Blown Fuse
Date Posted: December 01, 2004 at 9:16 AM

I have an 300W Peak Mono @ 4 Ohm amp with a 15A fuse hooked up to a 300RMS/450W Peak 12" Sub in Mono. The 15A fuse on the amp itself blows, but not the fused power cable to the battery, am I correct in saying the amp isn't matched up to the sub? I know the amp really isn't going to push this to 300W (it's a Power Acoustik).

When power is drawn from the battery to the amp, is it the amp that draws the power, or the sub?

I know the current is dependent on the load on the amp, in this case the sub @ 4 Ohms. And a 300W Peak amp should not blow a 300WRMS sub. But could the sub be asking for more power than the amp can deliver?

What do you suggest? A smaller 12" sub, or a larger amp? I have a bunch of stuff available.

I got into a little tif with a friend about this, and wanted your opinion.

Thanks,
DXAV



Replies:

Posted By: DYohn
Date Posted: December 01, 2004 at 9:46 AM
Does the fuse blow if the sub is disconnected?

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Posted By: dxav
Date Posted: December 01, 2004 at 12:34 PM
Not sure. That is a great troubleshooting idea.

If it does not blow, what do you think I should do (bigger amp or smaller sub)?

If it does blow, what do you think I should do?

Thanks, DYohn!

DXAV




Posted By: kfr01
Date Posted: December 01, 2004 at 12:38 PM
I highly doubt the sub/amplifier match is the issue.  There's probably a problem with either the amplifier or the install.

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New Project: 2003 Pathfinder




Posted By: dxav
Date Posted: December 01, 2004 at 12:45 PM
Well, the install was easy.

    8Ga Wire fused (30A) from the battery, straight to the amp. Grounded with an 8Ga wire to the chassis, exposed metal, large screw, with a solid connection.
    RCAs along the non-power side of the car.

That is really all I have to worry about.

kfr, what do you mean something wrong with the install? The amp is new, and hasn't run hot, either. Tons of space for cooling, too.

    What causes and amp fuse to blow? Obviously, if the power and ground touch, but they have spade terminals and are screwed tight to their appropriate locations. The remote is on fine, too. What else would cause this fuse to blow?

DXAV




Posted By: Francious70
Date Posted: December 01, 2004 at 1:38 PM
1) It's the amp that draws the power, the sub is the load.
2) You could have a bad amp.
3) Somthing in the amp may be grounding out.

Paul

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Posted By: DYohn
Date Posted: December 01, 2004 at 3:04 PM

dxav]N wrote:

t sure. That is a great troubleshooting idea.

If it does not blow, what do you think I should do (bigger amp or smaller sub)?

If it does blow, what do you think I should do?

Thanks, DYohn!

DXAV

If it does not blow, the amp is OK and there is a problem in your speakers.  If it does blow, the amp is toast and will need repair/replacement.  The idea of the fuse blowing because your amp is "too small" or the sub is "too big" is wrong.  This has nothing to do with blowing a fuse, unless the impedence load of the sub is too low for the amp or the sub or wiring is shorted or grounded out.



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Posted By: dxav
Date Posted: December 01, 2004 at 3:13 PM
Thanks for the replies, everyone.

DYohn, I didn't think the too small/too big idea made sense. I know the amp is 4 Ohm mono, and the sub is a 4 Ohm SVC. So that part is ok.

I will have to look at the amp and sub this weekend.

So, what would cause the amp fuse to blow?

Francious70, I know the amp is ok, there is only 1 Ground spot, and it is solid. No cables are close to the others on the power connector.

So I know the amp and sub can work, but it this a good configuration?
Just so we have this right:
1 300W Peak 4Ohm Mono Amp
1 300RMS/450Peak 12" SVC 4 Ohm Sub

Thanks!
DXAV




Posted By: kfr01
Date Posted: December 01, 2004 at 3:16 PM
You could stand to run more rms power to the sub, but depending on the efficiency of the sub and your listening habits you could be just fine. You'll have to be the judge of whether it is enough power for you.

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New Project: 2003 Pathfinder





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