I'm installing 1200W Amp and subwoofers in my car.
I have a 30A fuse inline from the battery.
The Amp has 2 15A fuses on the backside of itself.
As soon as I crank the car, the 2 15A fuses blow.
What should I look for as the cause?
Any help is appreciated.

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Replies (2)

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compvr15s on 03/23/2003 19:49:29
first id check all the wiring, maybe your ground and your positive are switched. or maybe somthing is jumping current from ground to positive. i had that happening on my ole amp and it would blow the inline fuse right when the cd player sent power to the amp. im not to sure on this idea but maybe your postive wire is bare somewhere and its grounding out, i dunno if that would do it or not. good luck

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Swez on 03/24/2003 14:51:45
Blowing fuses in the amp are usually a sign of shorted speaker connections or damage to the amp internally. Most newer amps have short, thermal and low ohm protection circuits. These circuits usually will go into protect mode if speakers are shorted etc.

Try removing the sub connection wires from the amp, then power it up and see what happens. If the fuses blow again, points to input wiring issues or amp problems. If the fuses do not blow, check your sub(s) connections. Try playing one at a time and see if the fuses hold.

Is this a newer amp? What brand and sty;e is this amp? MONO, 2 channel or other. Say more about subs being used as well.

Also, carefully check your input power wires and make sure they are connected to the proper terminals. If your polarity is reversed, this may cause your amp fuses to blow. Also, make sure your grounding wire is fully grounded to bare metal connection to floor pan, body or chassis frame. A short ground wire is recommended, same gage as the power feed wire.

FYI: This amp may say 1200 watts.... but here's the real deal:
Input current: 15 x 2 = 30 amps
Assume 13.5 volts input x 30 amps = 405 watts input draw
Output of typical ClassA/B amps is ~60% of input...
so, 405 x.60 = 243 watts total to speakers. If this is a Class D Mono amp, output could be closer to 325 watts total to your sub(s).

Finally, how are you feeding audio input signals into the amp? RCA lines off the HU, speaker feed taps off the rear speakers or some other method?

Swez

PS If these quick check do not produce a working amp, may have to get a tech involved and check out your amp. There may be internal problems causing the fuses to blow or you are trying to use it in a way it is not designed for.

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