jim010

I managed to figure out the amp, but I still don't know what this 'shield' is.
Also, in the attached wiring diagram:

Coming from pin #24 on C290D and onto C210, the wire leads to a shield. This shield seems to have something to do with all the wires going to the amp. What is this shield, and do I need it?

Thanks in advance.

Cheers

jim010

42 views and no one can answer?

cfraser

The shield is a metallic wrapping around the wires in a cable, and it's typically connected to signal ground (-, chassis) at one end (only), that end being the signal source end. Its purpose is to help keep some noise out of the audio signals. The shield here may be braided copper or some kind of metallized mylar wrapping.

jim010

Thanks. That helps alot.

So I need to get a wrapping around all the wires - some sort of sheath? And the wire coming from the ACM connects to this sheath?

jim010

Also, does it matter how close or far to the amp I put the shield? The amp is in the trunk.

dmhines

The Shaker 500 Amp should be on Driver Kickpanel under Dash ...

jim010

I do have that amp to the subwoofers under the dash as well as well. But that amp is only to the subwoofers.

This is a second amp that is found in the passenger side in the trunk that I didn't have. I have the amp and the bracket now. This amp is for the other speakers. I was just waiting to hear back as to what this shield is before I installed.

I think I'm ready.

dmhines

Thought only Shaker 1000 had Amp in the trunk ... I have a 2012 w/Nav but never knew there was another AMP back there.

cfraser

Does the cable from the ACM not already have a shield? According to the schematic that cable does already, all except the lowest wire are surrounded by the shield.

If you are making your own cable from the ACM, note that each speaker has either a twisted pair and/or is shielded as an individual pair too (both for noise reduction). Most decent audio/control cables you'd buy with 4 twisted pairs (say) in them would have a shield already. If the shield material is metallized mylar, there would be a "shield wire" (uninsulated) that you use to connect the shield at the ACM end...it's pretty obvious when you see it.

jim010

It is another amp for a nav car for the speakers. Here is a shot of the amp. This is the amp in the wiring diagram above that goes in the trunk. You should have this, but it is possible that later 2012s swtiched to having a built in amp in the ACM?

The amp goes in the trunk where the bracket is in the picture below.

jim010

Thanks again. I am wiring it myself from the connector 210 from the dash. From there straight to the amp as shown in the diagram. Everything you have said has made this all make sense to me now. To conform:


1) So I should make sure the shield wire is bare, not insulated.
2) I should twist each paring of wires (wires dedicated to a single speaker)
3) The shield can be located at any length between the connector and the amp.

Thanks for all this!

jim010

... or does this shield have to run the entire length of the cable?

cfraser

The shield should cover as much of the signal cable length as possible, just remove enough outer cable sheath so the wires and shield can be connected.

If you are not using a pre-made 4 pair shielded cable, you might want to consider just using regular shielded audio interconnect or microphone cable. These typically have 2 conductors, usually twisted, plus a copper braid shield. At the ACM/dash end you would connect the 4 shields together and connect to the Shield terminal (goes to ACM terminal 24). Radio Shack (for one) has cable like this that'll work. I myself would use a Belden (say) 4pr. shielded control cable, but they're kinda stiff.

The shield conductor in cables that's meant to be connected always is uninsulated. Not sure if that's what you meant...

I'm not recommending this, but a shielded Cat6 network cable has 4 twisted pairs in it, plus the shield obviously, and is cheap in quite long lengths even if you have to cut connectors off.

Edit: doh, forgot you were in Canada, no RS...maybe The Source then.

jim010

You are my hero of the day, thanks!

jim010

This is what I need, right?

jim010

Another member got this illustration for me.

cfraser

Yeah, that cable looks like it's fine, has all the basic goods you need. The only thing I caution is the labor is the big deal here, so don't cheap out on the cable so you have to do it all again...

jim010

The diagrams call for 22 guage, but I am only finding 24 guage.

Is the thinner wire going to be a problem? Otherwise I have to order online, as I can't find stp 4 pr 22AWG. It is mostly unshielded and in 24.

cfraser

Not much diff between 22 and 24, and the wires aren't carrying much current anyway, so 24's OK if that's more handy. But yeah, going too small a gauge was what I was thinking when I made the previous "cheaping out" comment. Like 28 gauge is not uncommon in cheap multi-pair cables, I was thinking you might be getting that. Also, try to get pair wires that are stranded if possible.

jim010

Stranded, not solid. Got it, thanks.