help with amp install - speaker level input?

[honder]

I am splicing off the rear deck speakers and going to speaker level inputs on the amp I am installing. The amp only has left/ground/right for the speaker level inputs. How do I connect the four speaker wires to the 3 connections on the amp? Would it be correct for me to put the negative wires together from the left and right speakers, and then connect that to the ground? (the amp was given to me so it is missing the original plug that most likely would have answered my question)
Thanks for any help.

 

[xplod1236]

Only take the positive wires from each speaker, and use a chassis ground for the ground connection. By connecting the negatives together, you will parallel 2 channels of the headunit, and since the signals will be different (stereo not mono), large currents will flow between the channels overheating and possibly frying the headunit output chip(s).

 

[unmibh]

Hi Honder,

You should be alright there with combining the two negative from left and right.

Connect the speakers directly to the output of the booster amp, do not connect them or even make contact with the body( chassis) of the car as most amp are design with a bridge amp and this means both the positive and negative output of the amp are active, may not be applicable to you but just a precaution.

I hope these help.

cheeers
unmibh

 

[Perry Babin]

That sounds like an older MTX. If so, do yourself a favor and go buy a Line Output Converter (LOC). Then use the preamp level inputs. It's the safest, most foolproof way to make the connection between the OEM wiring and the amplifier. If the LOC has brown ground wires, ground them to the closest available ground point to the LOC (no need to extend the wires).

Do NOT combine the speaker negatives. It can result in some very costly damage.

 

[xplod1236]

.....as most amp are design with a bridge amp and this means both the positive and negative output of the amp are active

That's exactly how headunit outputs are. Both sides are driven (pos and neg), and paralleling 2 unmatched channels (negatives of right and left channels) can and probably will result in damage.

 

[unmibh]

Hi Honder/Xplod1236,

You may be right, I think it willl be better if a qualified tech check out your head unit before conneting them.

With most head unit that I know , the a main amp are normally single ended as opposed to bridge.

Just to be safe , I will retract my advice to connect the negative for left and right to connect to your amp.

Have a tech check the units first before hooking them up.

cheers
unmibh

 

[:xrow:]

I agree with using a line output converter. It's inexpensive and will be far cleaner than trying to adapt something for the missing plug from the amp.