Question about Dual 2-Channel Bridgeable MOSFET Amplifier (XPA4100) Car Audio Amplifier

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Very confused We hooked up this amp with a sub to an existing head unit that was installed by pep boys. When the install was complete we turned on the car and stereo, the light ignites red for a short time, then goes out. If we remove the ground wire, the led turns red. When we re-attach the ground the light goes out. My friend tested and said the amp is only getting 7 volts. How do I fix this? What causes this to happen?

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Re: very confused

Could be you have a bad connection at the battery or at the amp or it could be that you are using a battery source wire to the amp that is way too small. Is the voltage at near 12 volts when the amp is switched off? If it is then either of the two problems I mentioned may need to be addressed. Don't forget to check and see that your ground wire is big enough and short enough and attached to the chassis good enough to carry all the amperage that it must during operation. The size of the fuse on the amp will give you a pretty good indication of which wire size you should be using for both the ground and the hot wires to the amp. A side note: be sure to keep your ground wire very short. On the order of 18 inches or less. A long ground wire can cause some kinds of problems. Good luck.

Posted on Jan 11, 2007

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1 Answer

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The best place I've found for in depth information on audio installs is The Install Doctor. You'll find step-by-step procedures, color photos, wiring details, and even the tools required. I recommend that you begin with the "tech docs" link and read through some of the PDF documents.

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