Amps Protecting at high volumes

kdunn926 · 08-30-2005, 08:59 PM

Just within the last month, my amps (Alpine MRP-M350s) have been going into protect at high volumes. I have kept all my settings and wiring the same throughout the time I initally installed the carputer and now, this is a recent development.

My subs were installed with my factory radio by car toys until I could afford the computer, and they garauntee their work for life, so naturally i took it in to them. They put my Infinitys on a meter and made sure both voice coils were intact. They also did some testing of the amps, and told me they were functioning normally as well.

They pinpointed the problem obviously at the computer, saying that the bad ground (the subs use to hum before sound card initialization) was at fault and there was feedback in the system. I fixed the ground by grounding the sound card to the amp neg (-) terminal, however the amps still protect at high volumes.

Today I got conflicting results from the 2 tests i ran. First I unhooked one amp at a time to see if one was causing the other to protect, nope, both protect with eachother. I also noticed that when they do that the digital readout on my 2 1farad caps drops to 8-10 volts. I shut down the computer and the voltage went back to 11+.

The second test I ran was using a different audio source with the computer turned off. I plugged an iPod directly into both amps and ran a subwoofer test on them, they protected when it became too loud (about 75% volume).

Between these 2 results I have not-so-narrowed it down to the amps and the computer, but it is unclear what may be the overall problem with the system.

Any ideas?

Jcarere · 08-30-2005, 09:14 PM

Even 11 + volts is not good for your amps. If this is with your car running then your alterantor or battery may be bad. Your amps allong with your computer at high volume may be drawing much current for your batt / alternator to handle. At that volume your car may be providing to little voltage and your amps go into protect. But since your computer has a larger voltage range the computer continues to run. If your car was off for those reading try running it and do the same test but also monitor the voltage at the amps at high volume just below the known volume limit and see how low they are. IF the voltage is low your battery or alternator may be going out and may need a new one. Give that a try and ghood luck.