help with speaker level input on an amp needed

[mikeinaustin]

I have a new elf E2125x amp, it is essentially the same as the arc 125.2 mini amp.

here is my problem, i have looked at both amps instruction manuals and NEITHER mention the speaker level input connector (or that the amp even supports it).

The speaker level input connector supplied by elf is like most amps, a connector that plugs into the amp and out of that connector are x wires. connect your speaker wire to the appropriate wire from that connector, etc.

however, unlike other amps i have used there is an additional ground wire coming out of that speaker level input connector. this is not the ground for the amp, that is on the other side of the amp located next to the +12v power connector (and next to the remote turn on when using line level inputs). just to help you visualize things, for a 2 channel amp, the speaker level input connector will usually have 4 wires (right +, right -, left +, left -). On this elf connector there are 5 wires (the 5th being for ground).

So the question is, what is this "speaker level input ground" for? In searching the internet, some folks connect it to a bolt on the head unit via a wire, some people connect it to a bolt on the amp itself and some people connect it to the same place the amp ground goes to.

what say you?

 

[mechanicx]

I think the separate ground wire is for radios that have a common ground for speakers, which isn't too common anymore. You should be able to ground that wire to any good ground. The amp's ground should be good.

 

[robshelton]

mechanicx is right. That ground wire is probably for a "Common ground" system that to the best of my knowledge is not used anymore. Just to be on the safe side, I'd probably run it to ground with the amp's ground.

 

[mikeinaustin]

so on one side of the amp is the speaker ground wire and on the other side of the amp is the amp ground "screw"(where your spade connector for the amp ground wire would attach to). can i just put a spade on the speaker ground wire and connect it to the screw where the amp ground wire spade connector goes to [the other side of the amp ground wire attaches to the car chassis]? in other words, just have a wire looping around from one side of the amp to the other?

 

[mechanicx]

I think that is correct.

 

[Jimmy9190]

The black ground wire at the high level input plug is a signal ground, not a chassis ground. You would ground it to either the same ground point as the electrical ground for the amplifier and the head unit should be grounded to the same point also. However, you should not need to connect the signal ground at all, unless the system either has engine noise or system noise. The signal ground is also sometimes used to improve the bass response, depending on the outputs from the head unit.

It would be easier and sound much better if you bought a line-level convertor and changed the high level speaker outputs from the head unit down to low level RCA inputs. Make the connections for it at the head unit and use good quality shielded RCA cables, and route them on the opposite side of the vehicle from the power wire(s). Don't route them near computers, body control modules, fan motors. etc. That reduces the chance of noise in the system. You can also buy a line level convertor that has adjustable gain controls to match the output to the amp to the output from the head unit. Using a line level convertor sounds better, gives you much more control over the system and is a much more reliable way to interface the amplifier to your existing audio system.

 

[bigmike]

Originally Posted By: mechanicx
I think the separate ground wire is for radios that have a common ground for speakers, which isn't too common anymore. You should be able to ground that wire to any good ground. The amp's ground should be good.


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