Question about Alpine PDX-4.100 Car Audio Amplifier

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Amp going into protect mode

I have an alpine pdx.100 running 2 type x component speakers in rear deck and two 6 1/2 type rs in my kick panels. whenever i turn them up loud the amp kicks off. if the gain is too high will this make it go into protect mode. I have alreafdy changed my alternator and voltage regulator. any help?

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  • dire1 Nov 10, 2007

    We are running the line level output



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If you set the gain too high on the AMP, at loud volume levels some clipping or distortion of the output signal will occur. Most amps have a Circuit inside that detects this clipping or distortion and applies protection to prevent damage to the speakers and the amp. It would help to know if you are driving the speakers with a Line level output or using the speaker output from your deck. There are many things that can cause an amp to go into protect mode, and knowing a little more about your setup will help to solve the problem.

Posted on Nov 09, 2007

  • Joseph
    Joseph Nov 13, 2007

    Setting the Gain too high will cause the protection circuit to turn on.

    The best way to set is as follows:

    If your amp has a Clip indicator LED, you should set the gain so that the LED barely flickers when you are playing at loud volumes. If you dont have a Clip Indicator, adjust the gain to just below the point you start the hear some distortion in the output signal.

    If that still does not fix the problem, try the following:

    Double check all your power and ground wiring. Make sure you have good, solid connections on your power feed wires from your battery and a good, solid ground connection close the amp. If the connections arent good it can cause power loss through the wires which can contibute to Clipping and Protection problems.

    Excessively long (20ft or more) power wires will cause these problems too, and you may have to try using a larger gauge wire (4 or bigger on long runs!). Most Amps will draw almost 10-15A of current under heavy load and this can result in a loss of about 3-5v at the amp end of the wire so your amp only sees 7-9v of the actual 12 you want to give it. This can be alleviated by using a capacitor (1F or so), if you have the money, but it may not solve the problem. If you can, shorten your power supply wires and try a different ground.

    Also you can check your speakers to make sure their impedance or 'Ohms' are within the specs for the amp. Check your owners manual for your speakers and amp to get this information, or look it up on line. Most amps like about 4 ohms or more to work properly. It may also be printed or typed on the bottom and back or your speakers and amp.



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