I picked up a Sony 4 channel amp (XM-554ZR) and 10 inch subwoofer (XS-L100P5W) at my local Walmart. The amp is 55W x 4 and the rear channels can be bridged. I set the amp up with high power sensing (not RCA's) from the rear speakers. I connected the left and right rear speaker power to feed the front and rear channels on the amp. From the amp I hooked up the front output to power the rear speakers and I tried to bridge the rear output to the sub. In bridged mode, I only hear the sub if I switch the balance either all right or all left. With the balanced centered the sub goes away. I tried reversing the connections on the sub and the same thing happens. I then hooked the sub up to only the left channel and it sounds great.

My question is what am I doing wrong? The sub sounds great to me but it is only getting 55W (4 ohms) since I am only running it on the left channel. With bridging the rear channelI can get 170W to it but it doesn't seem to work. Thanks.[/align]

 

Questions

1. Did you buy a 4 channel amp to only power a sub?

2. That wiring description is really complecated. Let me disect it.

You should have the rear speaker wires going directly to the high level inputs (Both front and rear as you have described). You should then hook the sub up to the front channel (bridged). And finally, the rear speakers should go from the outputs on the amp direcly to the rear speakers. If you have it wired like that you should be ok.

 

yeah if u just want for a sub best bet is to get a mono amp..

 

Thanks PReal. I like the 4 channel amp since it has more versatility. It had the ability to power a sub on the rear channel bridged. The rear channel has the LPF and the front channel has the HPF which I keep turned off since it does go the rear speakers (6x8's)on the rear deck. You got it right except for this amp...the bridged circuit is on the rear channel. It is shown as a diagramon the back board where theconnections go.

The connections make sense to me but it doesn't work that way. There must be something I am missing, but what?

 

Make sure you high pass the rear speakers, but keep it around 80hz. Make sure all of you wiring is separated and that you don't have any crosses wires.

That four channel will be a great starter amp, and will leave you with plenty of room to upgrade later.

 

Do I have to connect a jumper wire between the +/- of the two channels in order to have a bridge? Then use the remaining two as the power output. I am referring to a Sony amp that has a bridgeable rear channel.

 

No, that would cause a short. You just need to connect the positive of one channel and the negative of the other. They should be marked.

 

Thanks.....I don't get it...I set it up per the manual and the sub volume is much better when it is hooked to either the left or right channel despite it is only driven with 55W that way versus the 180W bridged. Sometimes I hate electical stuff....

 

Take some pictures and that might help.

 

I checked the wiring and it appears that the rear deck speakers were out of phase so I switched the + and - on one of the rear deck speakers coming from the amp and the rear deck speakers sounded much better and were in phase. The rear channel of the amp (where the sub is connected) did the same thing although I noticed the sub worked fine when connecting both +'s from the right and left channel....what's up with that?

I think what would help is if I knew the + and - connections from the factory Ford wiring. I sort of guessed this way:
Left Rear - Grey/Lt Blue (+) and Tan/Yellow (-)
Right Rear - Orange/Red (+) and White Purple (-)

Also, here's a pic of the back of the amp:



[IMG]local://upfiles/12481/A43E99628F4644508CDC832C9439CF9C.jpg[/IMG]