hey guys im running an Alpine CDE9874, 2 JBL GTO 1202D and a kenwood KAC-7201 amp in a custom slot ported box..i got 5 gauge wire running to the amp for power and 9 gauge ground from the amp and i have done the big 3 switch with 4 gauge wire cuz my systems only like 500 watt RMS ..now the problem is when i turn the volume to 20 or higher my subs cut out but the speakers still play..the deck volume goes to 35 clicks..i've set my gains and LPF and stuff (i did it with the DMM) but i would just like to know why it would do this.

 

My subs cut out at 20 or so, i have the 9886 and i think it is because the amp is either not powerful enough to handle the load or the subs can't

 

well...first off...run the same size wire to the ground as you would going into the amp. (ex 12 volt - 4 ga ground - 4 ga) i do know those subs are dual 2 ohm voice coils so i've gotta ask how there wired? there's a couple different reasons that jump out right off hand. 1 - the amp is wired at to low of resistance which is why i asked abotu how the subs are wired. 2 - that ground wire isn't going to allow alot of current to flow through it causeing low amounts of power to get to the amp. i'm willing to bet that if you drive around with your stereo as loud as you can play it now that ground wire will very likely be warmer then the positive wire. the other thing i would check is make sure all the connections are clean and solid. as for being able to turn your deck to 35..they've gotta reach a max output somewhere...doesn't mean everything will have the same max output.

 

yea ill throw a 5 gauge ground wire on and see what happens..i got them wired up series so i have a final load of 2 ohms.. all my connections are solid

 

For the length of the ground wire off the amp, you might as well get a couple feet of 4AWG instead of 5. Do it right the first time.

If the amplifier can't pull enough current to do its job, it'll go into protect mode. Sounds exactly what's happening in your case.

Start with upgrading your ground, if that doesn't solve anything, move on to the next easiest "fix".

 

Dave, don't sell him short, you know he can go to 19.9 and not 20.

 

You are fortunate, the band Spinal Tap could only turn it up to 11

I assume after a brief period the amp turned itself back on. So is 20 loud, is the amp putting out full power? ABSOLUTELY upgrade the wiring, and make sure all the connection points are tight and electrical connections are bare metal to bare metal. Also make sure the amp is located where it can cool itself and not covered with a blanket or something.

The sub amp isn't huge but here is a question is it distorting at 20? Is your amp for the HF and mids as loud as your sub up to 20? If it is distorting or the HF/ mids aren't keeping up then try turning down the amplifier gain and that could help.

There are several possibilities and this addresses 3 of them (too much heat, too much gain, and too little electricity). A fourth is a possible voice coil failure