speaker noise coming from speakers wired to amp

Hello I have a precision power amplifier model i10004 4 channel that I hooked up to four pioneer speaker model TS-D6802R. Ran new speaker wire to all four speakers. RCA were run separate from power source. the issue I am having is that after everything was wired and powered everything up you can hear a hissing noise from the speaker. removed the amps rca and you could still hear the hissing noise even tho the rca were not plugged in. To make sure that it was not my set up I removed the amp from the vehicle and tested on a bench where all wires were free from being pinched. and I still had the same noise coming from the speakers. could it be the amp??

P.S. I tested 3 other 4 channel amps on the bench and had the same noise on the speakers. Than wired a 2 channel amp and there was no noise. so I'm wondering if the noise is normal on all 4 channel amps. thanks and hope somebody can help

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Knowledge is Power.

You don't have adequate grounding. Get some good quality ground straps from the auto parts store. Install one ground strap from your engine block to the firewall, one ground strap from the alternator mounting bracket to a frame rail.
You are spinning your wheels looking for an equipment problem. You'll never fix it if you don't have plenty of grounds.

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Pegleg Charlie
Builder-Charlie Cannon Subwoofer Enclosures and general troublemaker at
LMMFAO Corp.(LOL)

pegleg 1960 I borrowed a JL Audio 4 channel amp from my cousin which he has running on his vehicle with no issues. I installed it to my car with the same set up that i have for the power precision amp. and the noise in the speakers was not there anymore. so I'm assuming that my set up is very good grounded and non of the wires (rca, speaker wires) are pinched. So i assumed that its a defective amp becase when i installed my amp (power precision) on to my cousins vehicle he got noise on his speakers. What could have happened to the amp for it to do that??

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Knowledge is Power.

Turn down all gain controls of the PPI amplifier. Does the noise go away? Turn both of them all the way down.

I have turned the gain controls all the way down and the noise does not go away. I tested the amp and a vehicle that does not have that issue and the noise is still there, so i think that the amp is the one with the issue. Is there a way to test the amps as to figure out why its making that noise?? because i know that my set up is grounded pretty good because i tested another amp with the set up in my vehicle and there is no noise in the speakers.
thanks for all the help.

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Knowledge is Power.

If you're not going to listen to the advice from a guy with 30 years electrical experience, you're on your own. It seems that you are assuming a lot of stuff. Get your amp probe and Fluke 16 out and start checking circuits. You say you have adequate grounding, if I ask you exactly where all of your grounding straps are located on the vehicle, I'll bet you might be able to guess one of them. If that's all you know about your wiring, good luck sir.

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Pegleg Charlie
Builder-Charlie Cannon Subwoofer Enclosures and general troublemaker at
LMMFAO Corp.(LOL)

pegleg1960 I have installed ground straps from engine block to firewall and alternator bracket to frame rail with 4 gauge copper wire. the amp still makes the noise, even with the rca disconnected, what else can i do?

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Knowledge is Power.