system help. ground loop like sound coming from subs

[HondaSI 10+ year member]

Ok so my buddy has 2 mtx 9500 series 10s and with a ab150.1 amp .. in his 05 grand am gt. When he turns on his system sometimes (mostly the whole time its on) he has a hum or pop sound coming from the subs ... No engine noise at all. We have checked all wires to make sure they are not exposed in anyway , changed out the stereo , changed the amp to check that. And it still does it. So we pulled the box and hooked them up in his fiances car subs, and both amps play great .. so now we are stumped.. what could it be ...

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[gckless 5,000+ posts]

So it's definitely the wiring, more than likely your thought of grounding. Have you checked or changed your grounds? Where are you running your grounds to? What size wire? How are they grounded, ring terminal and bolt to somewhere or grounding block? Need some more info here. Hard to chase down a problem without knowing all variables.

But if he changes his mind and decides to sell those subs, let me know //content.invisioncic.com/y282845/emoticons/suave.gif.858fc102f7646e678ee8af7e1fbc41d1.gif

 

[HondaSI 10+ year member]

4 gauge wire. Yes moved the ground its grounded to metel to metel where the backseat bolts to the car.. all wiring seems great... No idea where else too look..

 

[gckless 5,000+ posts]

If you are running that ab150.1 at 1ohm, that wire size is not enough. You need 1/0AWG. That amp will pull more current than that 4AWG is rated for. That's potentially a fire waiting to happen if you are running that at full tilt. What size fuse do you have in there? And what size wire is in that other car that you tested this amp in?

I would suggest trying to move the ground. Do you know what kind of voltage you're getting at your amp? Low voltage would be an easy indicator for a poor ground.

 

[HondaSI 10+ year member]

Subs r at 4 ohm I believe and the amp is all the way down wire doesn't get hot at all... 40 amp fuse in the power wire ... Do u think Ur could be his rcas that's 1 thing we havnt checked .. the other car as 0 gauge wire

 

[gckless 5,000+ posts]

Can I ask why he has 9510's and an ab150.1, to run them at 4ohms with the amp all the way down? Seems like a waste of gear. Should have just gone with something smaller? That's besides the issue....

Why are you running a 40 amp fuse? Have you ever blown that fuse?

What sounds exactly are they making? Is it only when he turns on/off the amp? If it's constant, at what interval is it cycling? As in, how many seconds between each sound. And describe the sounds.

 

[quackhead 10+ year member]

bad RCA for starters.

 

[HondaSI 10+ year member]

He had the amp down because of the system loop and we changed the rcas today and wow its fixed can't believe that's all it was ... He has a 100 amp fuse sorry ... But thx all.

 

[HondaSI 10+ year member]

Oh told him u were interested in the subs he said for the right price he would let them go.

 

[gckless 5,000+ posts]

Good that you fixed it. PM me the right price.