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Followup To
Question -
I have had a stereo in my truck, with the amp under the passenger side seat with no problems for about a year, recently my old alpine amp started buzzing in one channel. I replaced the alpine with an older fosgate I had to get me by till I could afford something new. When I put the fosgate in, there was a loud noise if I listened to a game on AM radio, that I never had with the alpine. I have sense replaced the fosgate with a new alpine amp (100 rms per channel when bridged) the noise is still audible on AM, but just barely when I first start the truck in the morning. But now I hear a popping noise through the speakers when I use my wipers on intermittent, if I turn them on regular speed or high speed there is no noise, only when they turn off and on. I have grounded the amp with a wire I think is about 10g and about 8 inches long. I have been told the shorter your ground wire the better, is this true? I heard someone say that that the deck and amp should be grounded at the same place, that would involve a long ground wire. The place I have grounded the amp to is cleared of all paint for a good ground. The deck is grounded through a wiring harness, so I am not sure where the deck is grounded. Any suggestions? Thanks, Larry
Answer -
Hi Larry,
btw...This is best referred to as 'system noise' until you can better isolate the problem.
The initial 'buzzing on one channel' issue may have been a poor RCA cable/connection (or even a problem with the deck) and NOT the amp.
You have not told me the year of the truck or if the deck in it is factory or aftermarket, ect.
To be frank, I do not see a single component which you have described (make/model#) fully. Noise can enter a system about 8 different ways, so bear in mind that I am being asked by you to fill in a lot of blanks.
As to the ground wire... yes shorter IS better and it should be at least the same gauge as the power wire, larger gauge if possible.
Yes, the deck, amps and any other components should be grounded to the 'same location'... this is called a chassis ground and if your deck uses the factory harness (via an adaptor), you can be sure it IS grounded to the chassis of the vehicle.
"The place I have grounded the amp to is cleared of all paint for a good ground."
This is good... but only IF the place you used IS IN FACT, a good chassis ground!
Many times in trucks I will use the one of the seat mounting bolts for a good solid ground.
My Thoughts:
Though possible, it sounds like it is probably not the amp ground.
The vehicle may have a poor 'body to chassis ground'. Never use a body ground hoping it will do.
Depending on the year of the truck and its condition. This could lead to noise problems of the sort you are experiencing.
Might be bad RCA's, Might be a bad deck, or a poor body to chassis ground, a bad relay in the vehicle for the wipers. I can go on and on if I were to guess.
My 1st thought is to try and isolate the problem if possible. This can be tricky to do remotely [especially since I have so little info on your layout].
You can do things like unplug the RCA's from the amp.. see if the problem still occurs to help isolation of the problem, but I just cannot guess that far into how your is layed out, to be able to walk you through some of it effectively.
Unless you can give me specifics about the system and the vehicle, your best bet is going to be hiring a professional there locally to anylize, localize, isolate and fix the problem.
People will spill all of this information to a shop when money is on the line,... but they always seem to think I can do this for free, even without specific system information. :
If you had the install done, just talk to whomever installed all of it. They would be able to better help you.
I have no idea whether you did it all.. or what, Larry.
You are welcome to resubmit this and provide more info for me to consider. Maby then I can get you a less vague answer.
Sincerely,
Jerry Mael
Jerry, Thanks for the help, The truck I have this system in is an 2004 Ford F250 Super Duty Regular Cab, the deck is an Alpine CDA-9805, the amp is an Alpine MRP-F240. I did the install my self, this is a company truck and I get a new one every few years and can't afford to pay to have the system put in and out so often. After reading your response, I think what I have done is to use a body ground, instead of a chassis ground.. Can you describe how you ground to the seat mounting bolts, if sounds simple, but I want to be sure I do it correctly, do I put the ground wire under the head if the bolt, or put the wire in the bolt hole and the put the bolt in after it.
Thanks again, Larry
AnswerLarry,
Pull one of the seat bolts out and go to a hardware store or an audio outlet and purchase an '8 gauge ring terminal' for your ground wire. Be sure to get one that has a large enough mounting hole to fit over the threaded end of your seat mounting bolt.
You just need to strip the ground wire insulation back about 1/4" and crimp the terminal onto the wire securely. Once that is done, then you can place it on to the seat bolt, then re-insert the bolt into the chassis hole and tighten it all down carefully.
*Note this is the 'body' you are going into.. but on most vehicles, there is a good factory body to chassis ground (probably several of them), so this is a suitable 'chassis' ground (or in this case, the shortest route TO the chassis).
Also, if you cannot find one that fits over your bolt, you can cut the end of the ring with wire cutters and spread it [only if required] until it will fit over the bolt. The type of factory bolt used may require some adjustments to this method [as to exactly how you place it onto the bolt], so this is a general guide.
As to the wiper noise.. that sounds like a problem with the wiper relay circuitrys' ground and may be un-fixable, though a noise suppression device may help to mask it.
My guess is that the noise is coming in thru the RCA's or the amp itself.....somewhere after the head unit, so this revamped ground may cure everything.
PS. You may want to be sure that the main run of the power wire for the amp is not running near the RCA's. Use oppposite sides of the vehicle to run these if possible.
Best of luck,
Jerry
