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Audio bubbys - Amp troubleshooting needed


max power

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I just got my truck back from getting a new timing chain and head gasket (thanks Pat Decook) and, like a dumbass, tried to pull my bare speaker wires through the holes in the rear floor hot which seems to have shorted them.

Now when the inputs are plugged in, the speakers make a whining sound that increases with the sound of the engine. Doesnt do it when the inputs are unplugged. I would guess its a ground issue if it didnt happen as soon as I did that. The protect light isnt on and it still works, just sounds like shit when the volume is low.

The amp is a Kicker ZR120 from the mid 90's.

Any ideas?

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I always thought that was RFI from spark plugs and wires, alternators etc. this is why they put those little rings of ferrite on the ends of so many cords you see now. shit they're even on my power tools too.

http://ngksparkplugs.com/tech_support/wire_sets/faqs/rfi.asp

you had work done...I would suspect this is the cause of the issue

Edited by serpentracer
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And here I thought I was the only one rocking the old Kicker ZR amps!

Double check and make sure all the engine grounds are good.

This thing has been a beast. Its been thru 3 trucks. I think its got something to do with me pulling hot wires through the floor and grounding them out. I may be wrong though.

The engine wasnt pulled and no grounds were messed with. He did install a new positive terminal on the battery wire and I had to install a new battery.

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Definitely a ground or your picking up ground loop noise from the rca's.

I would check all battery grounds, amps, grounds then go from there. I can help you this weekend bubby

Cool, let me know when you are available. Ill buy you dinner.

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This thing has been a beast. Its been thru 3 trucks. I think its got something to do with me pulling hot wires through the floor and grounding them out. I may be wrong though.

The engine wasnt pulled and no grounds were messed with. He did install a new positive terminal on the battery wire and I had to install a new battery.

I thought there were a couple grounds on the head? Isn't there one to the valve cover, too? It's also possible that one of the ground wires got damaged when moving the wiring around, due to the age of the truck. Just throwing out some possibilities!

I'm sure that Rawlins will get you cleared up, though!

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The used to make an audio filter for this type of thing. Not sure if they do any more? It was a Radio Shack type item and it would filter out the high voltage signal from the alternator - you've described the classic symptom (noise gets higher or louder with engine rpm). Might be a band-aide, but I've used them in the past.

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I think only the block is grounded. Why would you need to ground a valve cover?

I will check the grounds tomorrow if I can find the time. Gonna be a busy day.

they ground almost everything in cars now. I've seen a lot of honda's with a ground strap on the valve cover.

This. Imports are known for putting an insane number of grounds on an engine.

Here's a link for ya to show the ones to look for:

http://www.yotatech.com/f116/22re-ground-wire-locations-guide-194413/

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Alternator whine - common problem.

Common answer - something like this;

b15n.jpg

Available from a lot of places. This exact model can be found here http://www.sonicelectronix.com/item_44157_Boss-B15N.html

Under $10

It filters out the whine before it gets into the amp.

Needs to handle more than 12 amps listed on the label, Streets!

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Needs to handle more than 12 amps listed on the label, Streets!

I'm sure they make them in larger capacities. This was a very fast google search just to get the idea. I've used filters like this before and they worked pretty well. Better than the capacitor across the wires kind which don't work so well.

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I'm sure they make them in larger capacities. This was a very fast google search just to get the idea. I've used filters like this before and they worked pretty well. Better than the capacitor across the wires kind which don't work so well.

But not as good as fixing the source of the noise!

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This noise is specific to the amp. No noise on the other speakers when the amp inputs are unplugged.

Also, this is a 1994 Truck. It has no grounds on the head or valve cover.

Edited by max power
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I seem to remember the alternator noise going away after I ran a bigger ground wire for my amp...what gauge ground are you using/whats it grounded to?

Its pretty fat, id guess 10ga. I have it grounded to the body. Not rusty and it has worked for 10 years. I havent had a chance to mess with it yet, but i dont think its a sudden ground issue. I think i fuckered up the amp, though i hope not.

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Its pretty fat, id guess 10ga. I have it grounded to the body. Not rusty and it has worked for 10 years. I havent had a chance to mess with it yet, but i dont think its a sudden ground issue. I think i fuckered up the amp, though i hope not.

Just an aside on the ground wire to the amp...

Almost everyone just runs a ground wire right to the body, which is correct, but most people forget about the other end of the ground circuit, from the negative terminal of the battery to the body. Have you seen how small they usually are from the factory? It's not a bad idea to run a bigger one to carry the large amount of current that the amp will be drawing!

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Just an aside on the ground wire to the amp...

Almost everyone just runs a ground wire right to the body, which is correct, but most people forget about the other end of the ground circuit, from the negative terminal of the battery to the body. Have you seen how small they usually are from the factory? It's not a bad idea to run a bigger one to carry the large amount of current that the amp will be drawing!

That could be a possibility. I just had to put a new battery in after the repair. I'll try to get an eyeball on it tomorrow.

You didn't happen to run your RCA cables right next to your power wire did you? RCA and power need to be run on opposite sides of the vehicle or the RCA cords will pick up emf noise from the power wire and whine/buzz.

I cant remember since I ran it all 10 years ago, but I dont think so.

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Oh, wasn't sure if it was a full re-instal or not....I don't see how grounding out hot speaker leads would damage the amp, worst it would do is get hot and blow the protection circuit. Something has to be amiss with your wiring or your grounding.

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