A couple days ago, I wired in a amp into my 1980 F-150, everything works like it's supposed to, but it sounds like the speaker is just thumping all the time. I'm not terribly experienced when it comes to car audio. Could this just be a bad ground or what? I tried moving the ground to a different place and that didn't help. Any ideas?

 

first of all everything is not working as it is supposed to if that is happening. do you have a multimeter? make sure the ground has around 12volts(i think) across the ground attached to wherever and the positive terminal

 

There may be a low-pass filter in your amp that is turned on which only allows the bass frequencies to go through. Check to see if yours has one.

 

The only thing that I remember seing on the amp was the gain adjustmentknob and it's set in the middle. As for everything working, I still get the sound I'm supposed to, but the thumping noise is in addition to that. I wondered if it could be my alternator, or possibly, the fact that I hooked the power wire onto the solenoid instead of directly to the battery, but I wouldn't think that would have any effect as it is still direct power

 

If you have another amplifier (or know someone who just has one they're not using at the moment), try hooking it up to see if the noise is still there. If it goes away, then it's possible something's bad in your amp. Is the thumping occurring at regular intervals, or does it seem to be random?

 

It's a regular intervals, like about 2-3 a second. Unfortunatley, I don't know anyone, other than myself, that's not using their amp.

 

I would think that irregular intervals would be a loose wire or something. Regular intervals sounds like a component failure in the amp. (I'm assuming that the thumping occurs regardless of whether the radio or CD is playing or whether the truck is running or not.) Another way you might be able to eliminate other components is to disconnect your RCAs from your amp and plug up a portable CD player to it and play it. If it keeps thumping, I'd suspect internal failure in the amp.

 

The noise you are hearing is from a bad ground! Use the Multi meter and make sure you have less than .5 ohms of resistance. May also just be a loose ground. Make sure you scraped the paint off the sheet metal where you grounded it.

 

Right on, I will give it a try on the morning and let you know how things went. I appreciate the help.