Amps

Re: Unexplained Amp Problems

TigerHeli — Thu, 02 Jul 2009 21:19:09 GMT

Three things jump out at me.

First off - a fuse is a passive device. Essentially its a thin wire that breaks if it sees too much current. If your seeing 12V on the front and 0.9 on the rear of the fuse, I would suspect and replace the fuseholder, b/c that makes no sense.
I'm not really big into setting gain with a voltmeter - if that's how you are figuring the amp is outputting 180W per speaker, I would suspect your measurements more than the amp. If you have a load cell or an O-scope to check it on, that's different, but most people don't.
I've never heard of low power causing an amp to suddenly make more power - that would be equivalent to my running my car out of gas and then filling it up and running faster 0-60 times - it's not completely impossible, but I would say it's highly unlikely. Maybe the breaker is having less voltage drop than the fuse was, but I don't think so.
Not sure why the signal noise, unless when you were checking the fuse you maybe re-routed the RCA's slightly.
Check all your wiring connections three times and then again.

Okay, that was 5 things.

Hope This Helps!!!

Re: Unexplained Amp Problems

blackchevy92 — Fri, 26 Jun 2009 03:22:08 GMT

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.

Re: Unexplained Amp Problems

ch15 — Fri, 26 Jun 2009 01:00:53 GMT

I tried a new battery, but the problems are still there.

Re: Unexplained Amp Problems

ch15 — Wed, 24 Jun 2009 00:36:09 GMT

Good idea Shawn. Thanks for the suggestion.

Re: Unexplained Amp Problems

Shawn — Tue, 23 Jun 2009 16:07:37 GMT

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.

Unexplained Amp Problems

ch15 — Wed, 17 Jun 2009 22:37:24 GMT

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.