I'm no audio expert but unless you grounded the amp to the stud under the forks or at the studs located near the battery that the battery uses, you may not have as good a ground as you think.

 

I'd look at the ground myself.
capt42a

 

Well... I am a stereo install expert (really & truly- 1st Class certifed installer for over ten years, trained in excess of 200 different installers) and capt42 & HarleyPingMan are dead on...and I've never, I repeat NEVER found a noise problem I couldn't fix. Our regional install manager worked on one car for5 & 1/2 hours for a complaining customer... finally asked me for help and I solved it in 15 minutes.

Enough of my ego...for me to help, I need these questions answered...

1) What brand of amplifier is it? If you start to tell me it's a pyramid or radio shack equalizer, then don't bother answering, just return it and realize why they cost only $40.

2) Have you verified your ground? I don't mean check to see if it's mounted properly. I mean, have you taken your DMM, set to resistance, and measured the amount of resistance from your ground point to the negative terminal on your battery. If you have not done this, then you cannot be positive that you have a good grounding point.

3) If you have done this, what was the reading of the resistance between your grounding point & the battery negative terminal?

4) Have you also checked the resistance measurement between the radio ground and the amplifier ground? What was the reading?

5) Have you checked the resistance between the RCA ground (the round portion..not the center pin) and the radio ground? What was the reading?

6) Have you checked the resistance level between the RCA gound and the amp lifier ground? What was the reading?

7) Have you checked the resistance between the radio ground and the negative battery terminal? Reading? (Many time the factory radio ground point can be imperfect)

The problem you described is most often an ground noise problem between one of the grounding points of your system that are mentioned above...hence all of the "grounding point" questions. All of the readings between all of the ground points within a system should be measuring .5ohms or less. Any more resistance than that between any ground points means you will have potential for a ground noise problem.

Let me know & I'll try to help.


MM

 

As stated before it is a Pyle amp....I have grounded it to the grounding stud at the forks. I have not measured the resistance...I guess that is the next step, I too thought this was a ground issue...I'll get out the meter and do some checking....Thanks Again guys!