It depends on how decent the stock wiring is...you MIGHT be able to get away with it for 50Wrms, but I would feel more comfortable upgrading to something a bit beefier. When you start talking 100Wrms then I get uncomfortable staying stock.

Whenever possible it's best to keep power and signal wires away from each other...but that isn't always possible. The amp trigger wire is low current, and reasonably low-voltage (12V as opposed to the 10s of volts running through the speaker wires)...the biggest concern from a voltage standpoint is that it's a DC signal, not AC.

It always has to be looked at on a case by case basis, but a long, non-shielded ire such as the trigger can act as both a receiving AND a transmitting antenna (receving some noise at one point and retransmitting it at another point). As long as it's running alongside shielded cables, such as the RCAs, you'll be fine.

 

thanks MacGyver, I will take your advice and run my own wires.

 

I've always been told that UTP is the best cable design for car audio (that's unshielded twisted pair)

And the power wire/signal wire seperation is questionable too as vehicles use the chassis as one large "wire" with the grounding setup.

But, I'm no engineer - and I put 2 runs of 12 gauge into my doors because you never know when you'll have a 2000 watt transient.

/snake oil for sale

 

If you have a choice, go with STP (shielded twisted pair), but UTP is nearly as good for most apps. Shielded RCA should always be used over UTP or STP, regardless...amplifiers are not designed to have inputs with high CMRR (common mode rejection ratio) which is where UTP is intended for.

While it's true that the chassis is one large ground, it should be considered a plane instead of a wire from that viewpoint. To argue against separation at that point, though, is silly. If you really want to help things out, don't use a ground pointnext to the amp, use a ground point next to the beginning of the power wire (i.e., if you tapped off of the battery, use a point near there) and twist the power/ground wires together as if they were UTP.

 

Sorry. Don't mind me.

 

You have to remember that noise is not transmitted by conduction. There is no current or voltage physically running from one wire into the other.

High Currents running in the Power wires will create a magnetic field withing their direct vicinity. This is a circular field encompassing the length of the wire. Any signal wire which is in the vicinity can have electrical signals(electrical)noise induced upon it by this magnetic field.

This is why you don't put power wires near signal wires. If you want to look it up, it'll be under electro-magnetic theory and/or the "Right-Hand Rule".

Any magnetic field produced by current running through the car's chassie would be Highly negligible.