I hooked up my new amp today, to the RCA jacks on my stereo. when I plug them in all the way at the amp, it makes a thud sound constanly, like a ticking. If I unplug the patch cable to just the center positive connector, it works fine with no thud sound. I have a good gold plated patch cable. Any ideas?

 

I understand the unplugging thing. I guess you mean you just barely plug in the RCA, only to dontact the center, not the outer, and you have no noise, but do you have music like this ?. Also, are you using any of the factory wiring to any of the speakers ?
Phillip

 

Your correct, I plug in just the center connector, and it works fine and the music plays great. I dont have any factory wiring, this is a `75 and I am pretty sure that I have everything right. I also disconected the patch cable from the head unit, and it still made the noise if i touch the two outer connectors together or to a ground. I think I have a ground problem. where should I ground the amp? right now I have it screwed to the sheet metal. I have the deck wired to my subwoofer using the speaker level out, is this a problem?

 

First, did you turn the gain down on the amp to see if it made a difference ? For the ground, to the sheetmetal is ok, as long as the sheet metal is bright under the screw, and, more importantly, the cab is also grounded to the engine,which ends up grounding to the battery. Your noise can also be coming from the deck because of the cab not well grounded to the engine. Now for the wiring of the speaker outs & RCA's, If you are using an amp to run your sub, and your deck has RCA's, use only the RCA's to provide music to the amp. Do not hook both the speaker outs & RCA's of the deck to the amp ! The right way to utlize the speaker outs of the deck is to hook them directly to your front speakers and door speakers,while using the RCA's to drive an amp, with the amp driving the subs.Remember to keep the gain as low as possible but still high enough to play the subs loud. Apply these tips & write back.
phillip

 

I dont have the speaker level and RCAs hooked to the same amp, I have the RCAs going to my front and rear speakers amp. and the speaker level going to my subs. I have elliminated that as the problem, I unhooked the subs amp, and it made no difference. I think the problem is somewhere in the ground, I have the deck and amp grounded to the frame. The engine has rubber mounts right? I cant find a ground strap coming off the engine any where, it probably got lost in all of the engine swaps. I have seen filters for RCA cables, would one of these help?

Dave

 

The speaker level connections go to my subs AMP not to the subs.

 

I understand you up to this point, but you need to provide a NICE ground strap from the frame to the battery!It would be NICE to have one from the back of the head to the cab also.This will make everything work better, not just the jam! You must have a 2 x4 channel amp on those RCA's ? I think it would better to put your sub amp on the RCA's and the other amp on the speaker outs. But, I don't know everything ?
Phillip

 

I think I have my grounds fixed, I ran a strap to from the bat to the frame. that fixed the thumping problem. One of my amps doesnt have speaker level inputs, so... my subs are in the bed, and I didnt want to cut a big hole for the RCA plugs.

 

You need a ground loop isolator installed between your deck and amp.