Last week I started experiencing some strange amp problems. I've got 2 amps, an Audiobahn A8000V powering my subwoofers and an Infinity 475a powering my door speakers.
On Friday, the A8000V cut out on my way to work, as if the power had suddenly been cut off. So when I got home that day, I tested to power cables with a voltmeter. The 475a had 12 V at the amp, but the A8000V was only getting .9 V at the amp. I tested the inline fuse, and it was getting 12 V at the front of the fuse and .9 V at the back of the fuse. No problem, I replaced the fuse with a circuit breaker. Now it gets the full 12 V at the amp.
Now both amps are operating seemingly fine at low volumes, but they are picking up a lot of signal noise that hadn't been there previously. However, as soon as I turned up the volume, the audio becomes very distorted and the 475a quickly goes into protection mode. I thought maybe somehow the gain had gotten turned up, so I tested that. Each amp was putting out a lot more voltage than what I had them calibrated to previously. Here's the weird part: While testing it, I put the gain on the 475a all the way up, and it was putting out 180 watts to each speaker. That amp is only rated for 75 watts x 4, and 180 watts when bridged. The A8000V was also putting out more than it's rated for. I can't think of any explanation why both amps would suddenly put out more power than they're rated for.
The bottom line is that now both amps are picking up a lot of signal noise that wasn't there before. Since they're putting out more power than they should be, I suspect some amp internals got burned out from operating at such low voltage. Although I don't understand how the 475a would have been affected, but it's experiencing the same problems as the A8000V.
Any help or suggestions that anyone can offer would be greatly appreciated, because I am completely stumped by this problem.
Three things jump out at me.
Okay, that was 5 things.
Hope This Helps!!!
2002 Ford Focus Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs
The first thing I would do is check your battery. A weak (old) battery can cause all kinds of problems and put a much larger strain on your charging system than you might think. I can personally attest to some very strange occurrences cause by a weak battery.
Shawn
Good idea Shawn. Thanks for the suggestion.
I tried a new battery, but the problems are still there.
The circuit breaker might be at fault. Put another fuse inline and see if the problems are still there. I have seen circuit breakers do very strange things to low voltage power lines.
1992 Chevrolet pickup; Jensen VM9412 HU; Alpine 4x6 2-way dash speakers x 2; Pyle Blue Label 4x6 3-way rear speakers x 2; Pyle Blue Label 12" subs x 2; Crunch GVP700.2 "Ground Pounder" subwoofer amplifier; Custom Subwoofer box