amp issue...

ghandi1492 · Post by **ghandi1492** » July 12th, 2006, 1:59 pm

K, i think i may have messed up my amp somehow. My system was working before but then i started to get a 'test tone' and no music out of the speakers. I took one of the speakers out and tested it with my home receiver and it played fine. so the speakers are fine. Now my setup is just the 4 stock speakers (replaced with aftermarket ones) my eclipse amp, and my blaupunkt cd player. The cd player is hooked up to the external amp. whenever the amp gets power, that god awful sound started to blare. Now, i unhooked my amp (remote, power wire) to test just the cd player. From the 8 wires (4 + and 4-) that arent being used to connect the speakers directly to the h/u, i got a pair and hooked up the speaker turned on the car and it played music. so the head unit is fine also. The only reason i am hooked up to an external amp is because when i had the shop install everything i wanted them to run some rca's and power/ground wires for any future install of subs. It cost me just the same for them to hook up my 4 ch eclipse amp to run the speakers in the door so I had them do both. Now it got dark before i could figure out what is wrong with my amp. How can i test the signal going to my amp? could the rca's have gotten bad or something. the signal out to the speakers is just a loud a-- high pitch sine wave. My amp is getting power, is grounded properly, and the remote wire is connected properly, and i have monster rca's that never gave me any noise/interference/whine when the music played.

I'm leaning to a shot amp. Is there a way i can test it with my multimeter??

Thanks

AJ

ghandi1492 · Post by **ghandi1492** » July 12th, 2006, 5:45 pm

oh yea i forgot to add, that when i was testing my amp with the multimeter(didnt really know what i was doing), i took some resistanace readings (negative of amp to each speaker output) and all but one showed the same number. i forgot what setting i had the resistance on(i think on 20k), but 7 of them had like .8 ohms and 1 had like 10.1 ohms.

does that mean anything for one the the leads out of the amp to have a magnitude difference in resistance?

thanks!

AJ

ariesdude · Post by **ariesdude** » July 12th, 2006, 6:01 pm

Unplug the amp inputs - if you still hear that shriek then either its your amp or wiring to the speakers. Otherwise its the input wiring that goes to the amp.

ghandi1492 · Post by **ghandi1492** » July 13th, 2006, 11:30 am

k...i think it may have been a loose rca from the back of the head unit. I unhooked everything from the amp and head unit. Plugged 1 set of rca's in, and had a speaker in the back of the trunk with me. I tested to front and rear of the right channel, then the front and left of the rear channel. the right channel was fine on both and there was no more 'test tone' sound. then i tested the left channel. the front was fine, and the rear played music but it was extreamly low. i switched up the front and rear channel rcas to the amp and i got the exact opposite. so i plugged everything back in and made sure everything was tight. only had time to test one of the speakers still in the door (took out 2 of them to test) but i didnt get that test tone anymore.

will a loose rca cause that test tone to occure?

now tonight i have to put everthing back together and make sure it still works.

at least i didnt have to splice wires and connect my speakers directly to the head unit....

Thanks all for the help!

AJ

ariesdude · Post by **ariesdude** » July 13th, 2006, 1:01 pm

ghandi1492 wrote:will a loose rca cause that test tone to occure?

Probably not - but a shorted RCA cable might cause that and the low volume. In all probability you need a new RCA cable - if you keep using the old one the HU might blow up.

ghandi1492 · Post by **ghandi1492** » July 13th, 2006, 2:09 pm

what if the rca came into contact say with another rca or something??

ariesdude · Post by **ariesdude** » July 13th, 2006, 2:20 pm

The RCA plug has a metal rod and a metal cylinder surrounding it - the rod is the signal and the cylinder is ground. So if the ground touches other ground it is not a huge problem. But if the signal touches ground then shortcircuit happens. You can test the RCA cable with a multimeter - just put it in resistance mode and touch the probes to the rod (signal) and cylinder (ground) (unplug the RCA cable at both ends first). There should not be any resistance value between them.