Amplifier Ground Noise

[Iron-Mike]

I've been living with alternator whine in my system for awhile now and I decided since I had my dashboard apart yesterday I'd try to get rid of it once and for all. I double checked all my wiring and connections and I believe that the ground noise is coming from the RCA terminals on my deck. I'm using JL Audio interconnects so I have shielded cables to begin with. I went as far as using totally separate interconnects and hooked them up to the terminals on the back of the deck and ran them straight acros the seats to the cargo space and into the amps. Still got ground noise so i know its not the way I ran the RCAs and speaker wire. (RCA and speaker wires run down the passenger side, power runs down the driver side. Remote turn on wire runs down the passenger side too). I have both amps grounded to one of the rear bench bolts and power comes from a fused 4 ga connection from the battery under the hood to a fused distributor block in the rear.

Anyone with suggestions on how to eliminate the ground noise in this setup? I fell like I'm going in circles checking everything several times over trying to see what I did wrong but I keep coming up empty handed. Oh and by the way ground loop isolaters didn't work when I hooked them up at the amp end of the connections either in case someone was going to suggest them...

Thanks in advance for any insight guys

Mike

 

[jluv]

I have both amps grounded to one of the rear bench bolts...

This is likely the cause of your problem. Ditch the ground loop isolators. Get a ground boot. Pick a flat spot of metal floor under the rear seats instead. Sand down to bare metal. Drill and mount the ground boot securely. Use at least 4ga ground wire since your power wire is 4ga. Make the ground wires as short as possible. If your problem persists, it very well may be the RCA connections on your head unit or amp(s). Good luck.

I never understood the use of the seat bolts as a ground. I sure do see it a lot, though.

 

[Iron-Mike]

so you suggest I not use the rear bench bolt but drill a new ground hole and mount the ground to that instead?

I'm not using ground loop isolators right now. I got some to see if they would help and when they didn't they went right back to the store.

 

[toypaseo]

Find a factory ground to ground to.

 

[Iron-Mike]

I don't remember seeing any factory grounds in the cargo space area or behind the rear seats. I used the seat bolt because it was used by several other people here and it worked for them. I'll try using a new ground location tomorrow unless someone has a better idea

 

[aznboi3644]

don't worry about finding a factory ground.

I'd ground directly to the frame if you can. Find a clear space you can drill through that you can access from underneath...put a grommet in there and ground directly to the frame...then cover it up with some pray on undercoating to protect it.

Also try getting a length of 18 gauge wire and ground the HU chassis to the amplifier chassis

 

[Iron-Mike]

seems the great minds all agree... run a new ground directly to the frame by drilling a hole with a grommet

so I'll stop by the store and grab a length of 4ga ground wire and drill a hole back there somewhere and ground to the frame like suggested. Hopefully this will solve my ground noise problem.

Thanks guys for the insight I seriously appreciate it

 

[Charlie]

I always hate having to find those grounds that do that. It's a real pain. Good luck!

What is was for me once, was there was a
+ in
- out
and a ground

I had the ground and negative both on the negative, the ground not actually grounded. I learned my lesson..

 

[Iron-Mike]

I checked like every single wire coming from behind the radio and when I disconnected the interconnects from the deck I got no ground noise even though they were still connected to the amps. As soon as I hooked them back up to the deck the noise came right back. I tried moving the ground wire from the deck to a different location but that didn't help either.

 

[aznboi3644]

I checked like every single wire coming from behind the radio and when I disconnected the interconnects from the deck I got no ground noise even though they were still connected to the amps. As soon as I hooked them back up to the deck the noise came right back. I tried moving the ground wire from the deck to a different location but that didn't help either.

did you try grounding the HU chassis to the amp chassis like I suggested in my earlier post??

 

[bp1506]

I know when i had whine once the cause was the actual head unit ground wire. I guess the black wire that was in the vehicles harness for ground was too good. I just found a good ground point and that was it.

 

[Infinity08]

Is the whining noise there when you unplug the RCA's from the amps? Also, is this a Pioneer head unit (notorious for jacked up outputs, but can be fixed)?

 

[Iron-Mike]

I took the headunit out yesterday and moved the ground wire to a new location which didn't help at all. I got a 4ga ground wire and drilled a hole in the factory sub location and scraped away the paint and grounded it there. No help either.

as soon as I took the RCS cables out of the deck the ground noise stops. I can leave them connected to the amps and theres no ground noise.

As soon as I put the RCAs back in the deck the ground noise comes back. And its in both the door speakers AND the subs.

I'm going to take it to a shop I'm friends with one of the installers at and have him look at it for me. I'm at my wits end with it. The deck is a Kenwood DDX6019 which I'm going to be switching in the spring to the DDX8019

 

[aznboi3644]

I took the headunit out yesterday and moved the ground wire to a new location which didn't help at all. I got a 4ga ground wire and drilled a hole in the factory sub location and scraped away the paint and grounded it there. No help either.

as soon as I took the RCS cables out of the deck the ground noise stops. I can leave them connected to the amps and theres no ground noise.

As soon as I put the RCAs back in the deck the ground noise comes back. And its in both the door speakers AND the subs.

I'm going to take it to a shop I'm friends with one of the installers at and have him look at it for me. I'm at my wits end with it. The deck is a Kenwood DDX6019 which I'm going to be switching in the spring to the DDX8019

try grounding the hu chassis to the amp chassis like i suggested twice?? lol

 

[Iron-Mike]

forgot to mention that I tried that first since you suggested it days ago... no dice. In fact it was the reason I took the deck out in the first place in hopes you were right, before I bought a length of 4ga ground wire and a couple terminals for it.

It seems ther is more than 1 ground wire for the deck though... I cut the ground wire that I had mounted behind the dash and the deck was still able to turn on and off like I never disconnected the ground. Which leads me to believe there is another one somewhere I'm missing but I didn't see it yesterday. Kinda weird. In the past if the ground wasn't connected a deck usually wouldn't turn on. For some reason this one does though unless I missed something somewhere...

 

[Infinity08]

Once you cut the ground wire, it will find another path to ground- perhaps through the antenna or chassis. It sounds like you have a messed up deck. I have basically teh same one, and it is dead silent, even moreso than the Alpine 7939 I keep as a spare. The problem is definitely in the head unit, but I'm not 100% convinced it is the ground. Humor me on this one.

Take a piece of wire 16awg or larger and attach it to the ground on the deck, and just run it outside the car straight to the negative battery terminal. Also, unhook the antenna while you do this. Check for noise on a disc as the source. If no noise, try hooking up the antenna (testing for bad ground through that line). If it is still clean, permanently run that wire to the battery and smile. If it gets dirty, replace the antenna AND the wire. They do go bad, and it happens fairly often, especially on the coast.

 

[Iron-Mike]

thanks for the advice. I can attempt that fix in the morning before I go to work. I'll post my results when I get in the office tomorrow morning.

After double checking the ground wires and the interconnects I was almost positive without a doubt that it was the deck itself and not something I did wrong with running my wires. I've done more than a few installs in various vehicles and run them all the exact same way with no ground noise. In fact i don't recall having ground noise in my system until I upgraded to the 6019.

I had the KDC-X990 deck prior to the DDX6019 and it never game me problems. Once I switched to the touchscreen I put the X990 in my ex girlfriend's Impala and wired it up the same way I did my explorer. No gorund noise in her system but I have ground noise in mine. Go figure

I'm thinking about taking another Kenwood deck and testing it in my system with no changes and see if I get ground noise. If I don't then I know its the deck

 

[aznboi3644]

Hmm...well I'm not sure what the problem is than.

 

[Iron-Mike]

I went back to the basics and took everything apart and started all over from scratch. I got a new wiring harness for the DDX-6019 from my friend at the audio store ($80) and a new aftermarket wiring harness for the truck from Best Buy ($20) and re-wired the whole thing as if there had never been a system in there. I double checked the interconnects, fuses and everything. At the end I reset the gain to match from the amps to the deck and put it all back together.

NO GROUND NOISE

not sure which of these things had the impact of eliminating the gorund noise but I'm glad its gone either way. So it cost me $100 and a couple hours but the noise is gone and I can drive without that irritating whining noise

Thanks to everyone for the suggestions on how to get rid of this