Interlagos Fire

Have anyone seen this type RCA before? Not sure what to do with the extra ground wire? If I'm not going to have to use them should I cut them off and put a crimp cap over, or electrical tape the ring?

Thanks

Ichigo

iTrader: (6)

some people use it for a remote amp turn on, if your not going to use it, just snip the exposed copper and wrap with electric tape on both ends

KPierson

iTrader: (1)

It's usually recomended to ground one end (and one end only) of it, to help reduce noise. I have no actual proof of this, but that's what I've always heard.

Interlagos Fire

Ok, will try to gound the end that connects to the amplifier.

Barmats

iTrader: (1)

Use a continuity checker to see if it's common to the ground or shield on the RCA connectors. It probably isn't and therefore will do nothing to improve the shielding of the cables. It is likely a remote turn-on wire as suggested above.

leemik

iTrader: (2)

it's pretty common when you buy automotive RCA cables..

and if you ever owned a turntable in your life they are usually two RCA's and a ground too

--mike

Interlagos Fire

So if it's a remote turn on wire then I don't need it right? cause the amp kit came with one (blue).

I guess I"m just not gonna use it to be safe.

I.F.

THE TECH

iTrader: (154)

Well you can use it instead of running the extra wire.

VO...

iTrader: (25)

The extra wire is used for your remote amp trigger wire, not a ground. The outer portion of the RCA jack, itself, is the grounding point for the RCA. If you've ever opened up the insulation on an RCA cable, you'll notice that the outer layer of the RCA is some type of wiring mesh. This mesh is connected to outer metal(copper/gold) portion of the RCA plug. Since the amp is grounded, any foreign voltage or inductance is shunted to ground by the outter mesh of the RCA cable.

KPierson

iTrader: (1)

In a world where everyone is always trying to save a buck and companies are continously trying to increase profit margins why would they include a dedicated remote turn on wire if the RCA cable has a suitable wire built in to it?

I'm going to look in to it more, but I'm pretty sure there is some connection between the middle wire and ground, but its been years since I've installed car audio stuff.

KPierson

iTrader: (1)

http://www.the12volt.com/installbay/...RCa&PN=0&TPN=2

Here is a post on a car audio forum about this. However, they, too, seem to not totally agree and support both sides of the use.

I personally don't see a problem with using it as a remote wire, as the remote signal is low current and constant, but if a dedicated remote wire is supplied I would use it, and run it with the power wire on the opposite side of the vehicle.

Hraesvelg

iTrader: (1)

+1

Barmats

iTrader: (1)

From the12volt.com forum post referenced above:

This is correct - this type of ground wire was often used in audio equipment when the shield of the audio connectors was at a different electrical potential than the chassis. Tying chassis ground to the shield would often reduce or eliminate residual hum or circuit noise. BUT, if it created a ground loop (by connecting both ends of the wire), then it would often induce noise/hum or make existing levels worse. Which is why the wire was often connected on one end only.

As for why cable manufacturers include this additional wire if there's no clear-cut reason for doing so -- it may be that there's a glut of these still around and are still being used, or that tooling costs to eliminate what's already in place is simply not cost effective. In any event, it's a good option to have whether used for additional grounding or remote switching.

StreetOC192

iTrader: (7)

Depending on the exact construction of the wire......

It looks to me from the pic that it is a drain wire. If the wire is interwoven into the braided shield of the rca wires. The braided sheild of the rca's 'traps' RF noise and the drain wire is used to ground the shield on the RADIO SIDE of the rca's to drain the noise into the ground loop of the car. Grounding on the amp side will not be effective. You want the noise to drain away from the amp, not towards it.

On some cheaper rca cables, they have a wire that is run in a banana-peel construction between the two rca channels and that is not a drain wire, but rather can be used for a remote turn on. I still don't recommend using this as a turn on either way.

KPierson

iTrader: (1)

I actually just looked at the picture blown up for the first time. That does look like it is intended to be grouned, why else would it have ring connectors on it?

I wouldn't do anything with it. Hook everything up, and if you have noise try grounding one side of it.

Interlagos Fire

ok, someone please explain to me what is a ground loop? I've known the term and read about it, but is not exactly sure what it is and how it occured?

Will I create a ground loop if I connect both end of this supposely ground wire? Or, like someone above said, better to ground just the radio end, not the amp.

From logic, I have agree it's probably a ground more than others, like kpierson said, why would it have a ring terminal if it's not intended as ground?
Also, in the kit that this RCA came with the manufacture included a extra remote turn on wire (blue) just for that.

StreetOC192

iTrader: (7)

Here's a great write up on ground loops.....
http://www.bcae1.com/glisoltr.htm

You will indeed CREATE a ground loop if you connect both sides of the wire to a ground. This will actually cause more noise to enter the signal path as there will be flow of noise through the drain wire. The drain wire should only be connected on one side and that side should be the head unit side. You should snip the other end of this drain wire off if you are going to use it as such to avoid confusion. I do not know why the cable was manufactured with 2 sides to the drain wire other than the possibilty of reversing which side actually gets plugged into the head unit side.

Barmats

iTrader: (1)

Excellent reference article.