Ground Loop?

[IDSkoT 5,000+ posts]

It seems a few people are having this same problem as me now.

I went to set the gains on my amp with a newly acquired Radioshack DMM, and my Moms asked me to move my car so she could get out. Prior to this, I had turned my car on and off maybe 3 times in the course of an hour. Trying to set my gains and I didn't want the battery to die, but I couldn't figure it out (and stil lcan't).

So, the last time I turned it off I heard a pop but didn't think much of it. When my mom asked me to move, the pop happened when the car turned on, and I heard alt noise (whirring sound that increases in pitch / volume when the engine's reved).

I'm guess it's a bad ground... maybe off the speaker amp? [i have a JBL 750.II or something like that... it's a 104x4 @ 4-ohm amp and a Boss 1200M which is 600x1 @ 2-ohm]

I also have a Pioneer DEH-P6900UB for my HU. Should I ground that and see if it helps? I kind of want to avoid pulling the HU out since I lost the clips for them and I don't want to scratch or break anything with clothes hangers if I don't have to.

Help?

EDIT:: and if it is a messed up ground-- why'd it just now start messing up? I've had that set-up like that for a couple of months now with the gains set at an audible level, rather than with a machine (DMM or oscilliscope).

Click to read more...

 

[IDSkoT 5,000+ posts]

/bump for love?

 

[dman4486 5,000+ posts]

ground the shielding on the rca's to see if the problem is the hu

 

[IDSkoT 5,000+ posts]

ground the shielding on the rca's to see if the problem is the hu

thanks dman4486, but how do I do that?

 

[dman4486 5,000+ posts]

let me find a pic

 

[dman4486 5,000+ posts]

I can't find the pic I was looking for, but there are two ways you can do this:

1. ground loop isolator from radioshack, or audio store(goes inline with the rca's and has 2 brown wires to run to ground

2. simply strip the end of a pair of wires and insert them in between the rca cable and the hu's plugs(contacting only the outer rind on the rca plug and not the center pin.....then run those 2 wires to ground

 

[IDSkoT 5,000+ posts]

I can't find the pic I was looking for, but there are two ways you can do this:1. ground loop isolator from radioshack, or audio store(goes inline with the rca's and has 2 brown wires to run to ground

2. simply strip the end of a pair of wires and insert them in between the rca cable and the hu's plugs(contacting only the outer rind on the rca plug and not the center pin.....then run those 2 wires to ground

So, if I get the ground loop isolator it's pretty much certain it'll fix the ground problem?

 

[dman4486 5,000+ posts]

So, if I get the ground loop isolator it's pretty much certain it'll fix the ground problem?

it is a solution for ground loops, and will prove it is the hu's pico fuse that popped

 

[ultimate157 5,000+ posts]

Here's what I did to fix my pioneer alternator whine

 

[IDSkoT 5,000+ posts]

Here's what I did to fix my pioneer alternator whine

lmao, nice. Did you just strip a bunch of wire and do that?

How can I pop my HU out? I lost the clip things. Do I just use good ol' fashion wire hangers?

 

[ultimate157 5,000+ posts]

lmao, nice. Did you just strip a bunch of wire and do that?

Sure did. Common practice around here to do so... Easy quick fix.

 

[IDSkoT 5,000+ posts]

Sure did. Common practice around here to do so... Easy quick fix.

Nice. I did it (for not 'till I get some bread to buy some actual ground loop protectors, and worked pretty well considering on what I used and how ghetto rigged it is. BUt, as I said, it's only temporary.

I was also wondering if anyone could tell me how the f*ck I get the volts to set my amps? I know what the voltage is supposed to be, but for some reason I get my DMM to work for sh*t.

Radioshack, eh?

It looks like a regular DMM

http://www.radioshack.com/product/index.jsp?productId=2103176&cp=&sr=1&origkw=digital+multimeter&kw=digital+multimeter&parentPage=search

For some reason, no matter what I put it against, and what settings I use, it gets some ridiculously low number. Can anyone please spell it out for me? I read the manual, and did what it said... and I guess I'm just retarded.

I turn it to the volt setting, I choose DC, and I prod the screws for the output with out the speaker cables in... and I don't get squat, man. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif HALP!

(And yes, tone CD on with no eq and bass boost down on 75% volume)

EDIT:: I did have a hard time getting those wires to loop around.. what I ended up doing was making a loop with my pinky, putting it around the jack and putting the RCA in, pinning it in, then used it to tension it and kinda wrapped it around the other... and repeated for my subs.

 

[danp129 10+ year member]

The voltmeter needs to be set to AC

 

[ultimate157 5,000+ posts]

The wire around the RCA terminals is better than any ground loop isolator or protector.

The isolator/protectors will only cover up the problem ... the wire is re-grounding the RCA's; This is the source of the issue.

 

[IDSkoT 5,000+ posts]

The voltmeter needs to be set to AC

Even when I set it to AC it gives me a low number.