Rcas Ground?

SamSagaZ

hey guys, im thinking abt how will pass the wires over the floor of the car, and i figure that the RCA´s have an Ground wire to connect to the ground of the car (i think), where can i connect it? is ok if i connect it to the chassis car?

another question.... someone know some url where can i get some schematics abt nice instalations?

and another one.... 4awg to the distro and later 8awg to each amp is ok?

MacLeod

Dont worry about grounding the RCA's.

4 guage then 8 guage is just fine.

Dont need any schematics.

Just run the power and remote wires down one side of the car and the RCA and speaker wires down the other. Or you can run the RCA's down the middle.

There are a lot of people nowadays saying its ok to run RCA and speaker wires next to power wires but I figure why not? It doenst hurt anything and its cheap insurance against noise.

SamSagaZ

so why the RCAs come with Ground? its for noise? or its not useful?

MacLeod

Honestly, I dont know.

However Ive never used them and have never had any ill effects from not using them.

SamSagaZ

i tested it a few minutes ago (the biamp the speakers using the rear channel) and honestly i dont like how my speakers sound, i dont ear any better... btw, im not happy with my set of mmc6500, maybe its because im using it from the HU and not amp already.....

i need to start saving money right now to buy the c400.4 and test it.... i don tknow if the sound is not good right now coz the HU have too much THD, if i put more than 28-30 of the volumen control, the sound sux... the top level is 40.

if i hear it using 20-25 the sound is good but not enough for my ears

btw... ill put the wires tomorrow (rcas/speakers/power) and maybe in 1 or 2 months i will buy the first amp (the c400.4) and hope the sound will be better

AustinKP

Originally posted by SamSagaZ
so why the RCAs come with Ground? its for noise? or its not useful?

You're probably talking about a built-in remote wire. Some RCAs come with the remote wire attached to them, so you just run that from the HU to the remote connector on your amp.
-Austin

SamSagaZ

well, i dont know its the picture of the wire.... the box say that its an ground wire...




as u can see in the middle of both wires (right/left) you can see another small wire... in the box say that its for connect to the ground :S

AustinKP

Originally posted by SamSagaZ
well, i dont know its the picture of the wire.... the box say that its an ground wire...

as u can see in the middle of both wires (right/left) you can see another small wire... in the box say that its for connect to the ground :S

The middle pin on the rca connector themselves is ground, so I don't know why you'd need an external ground. That wire is used as the remote wire.

SamSagaZ

ok, ill use it as remote

Jstas

Listen up, everyone.

Do you see that bare wire sticking out of the center of those cables between the two ends? You can see it on the background photo of the coiled wire.

That is a ground lead.

That ground lead's sole surpose is to provide a common ground for the RCA cables when an amplifier does not have a common chassis ground for the RCA cables.

Most modern amplifiers no long require them but there are still some models that do. I rarely see them and when I do, they european or japanese direct market models that do require them.

They are a non-issue however, I would not use them as a signal turn-on lead. The reason is that the lead carries "dirty" power and it can introduce intereference due to its extremely close proximity to the clean audio signal travelling down the interconnects. The best thing to do is to just trim the leads down so that they do not stick out of the ends of teh cables and be done with it. Unless of course you need them.

Jstas

Originally posted by AustinKP
You're probably talking about a built-in remote wire. Some RCAs come with the remote wire attached to them, so you just run that from the HU to the remote connector on your amp.
-Austin

No such thing. The only thing that comes built in to the RCA cables is the ground lead for connecting the RCA jacks at the amplifer that lack a common chassis ground back to the head unit that have a common ground. It can go the other way too where the RCA jacks on the head unit do not have a common chassis ground and utilize the chassis ground point on the amp for the RCA cables to work correctly.

AustinKP

Ah. I hadn't heard that. I based my comments on this.
They come with the third wire. They used to be described solely as the remote turn-on lead, but now they also say it can be used as a ground-loop isolator. Thanks for the clarification.
-Austin

SamSagaZ

ok, thanks Jstas for your great explination, i dont will use it

i think that mtx 810D or Polk C500.1 dont need that stuff.

Jstas

Originally posted by SamSagaZ
ok, thanks Jstas for your great explination, i dont will use it

i think that mtx 810D or Polk C500.1 dont need that stuff.

No, you are right, they shouldn't.

One thing I do not understand is how these companies can recommend using that lead as a turn-on lead when the loose end is barely long enough to reach the ground screw let alone the turn on lead. You'd have to extend it by splicing an extra length of wire on. Doing that creates another connection where noise and interference can get in.

If you want cheap turn-on lead wire, just go and grab some general purpose automotive wire from an auto parts store and use that. The turn-on lead doesn't have to be real fancy, it just has to carry a voltage to turn the amp on and off. The automotive wire will also last a good long time and will be more than enough to carry the simple signal.

AustinKP

Originally posted by Jstas
One thing I do not understand is how these companies can recommend using that lead as a turn-on lead when the loose end is barely long enough to reach the ground screw let alone the turn on lead. You'd have to extend it by splicing an extra length of wire on. Doing that creates another connection where noise and interference can get in.

I had to do exactly that - splice another wire to make it long enough. The noise and interference would be a non-issue though, since it doesn't matter how dirty the remote lead signal is. Unless, if you're talking about interference messing with the RCA signals. That could have effects.

Jstas

Originally posted by AustinKP
I had to do exactly that - splice another wire to make it long enough. The noise and interference would be a non-issue though, since it doesn't matter how dirty the remote lead signal is. Unless, if you're talking about interference messing with the RCA signals. That could have effects.

Nope. A bad connection on any power circuit, 12v switchable or 12v constant, will cause an EM field strong enough to affect adjacent yet seperate circuits and propagate itself through the entire amplification and signal processing systems. Running that dirty lead straight down the center of your signal can cause as much problems as wrapping your primary power cables with your interconnect wires. It's just a bad idea overall.

MacLeod

Originally posted by SamSagaZ
i tested it a few minutes ago (the biamp the speakers using the rear channel) and honestly i dont like how my speakers sound, i dont ear any better... btw, im not happy with my set of mmc6500, maybe its because im using it from the HU and not amp already.....

i need to start saving money right now to buy the c400.4 and test it.... i don tknow if the sound is not good right now coz the HU have too much THD, if i put more than 28-30 of the volumen control, the sound sux... the top level is 40.

if i hear it using 20-25 the sound is good but not enough for my ears

btw... ill put the wires tomorrow (rcas/speakers/power) and maybe in 1 or 2 months i will buy the first amp (the c400.4) and hope the sound will be better

The reason you dont like your speakers is because youre not powering them properly.

You say you like the way they sound at low volume, thats because thats all the power that h/u can make cleanly. When you hook up an amp to those speakers it will be able to sound like that at a much louder volume cause it wont run out of clean power as fast.

This is why we always recommend strongly AGAINST using the h/u to power ANYTHING.

SamSagaZ

thanks.