Loud humm with engine off...

[Motovet 10+ year member]

Just have the rears going so far in new install, and have a loud humm with system on...engine off. What should I look for? I should add the rears are amped.

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[supa_c 5,000+ posts]

ACC on or in start ?

Speakers h/u amped or externally amped ?

 

[Motovet 10+ year member]

The set up is the Pio 880PRS and the rears are amped. I only used a Profile 100W for those as I will rarely run them. I get the loud humm with Acc. and with engine running. The humm is the same both ways.

 

[JimJ 5,000+ posts]

Is the noise RPM dependent?

 

[Motovet 10+ year member]

No. Well to be honest the Tahoe is in the garage as install is still in progress, and I didn't run the RPM's up to see. Also with the loud exhaust I don't know that I could hear it. The humm is only audable with the volume down....when it's up you can only hear the music.

 

[Motovet 10+ year member]

Grounds seem to be good. Checked the Zed amps, and they have the same noise. Ideas?

 

[thatkidbob 10+ year member]

Hook something up to the amps besides your p880... if you've still got a hum i'm thinking its grounding related.

If it goes away check grounds on your HU.

 

[matrxx dude 5,000+ posts]

check your rca cables

 

[Motovet 10+ year member]

Thanks. In what way should I check the rca's?

 

[matrxx dude 5,000+ posts]

the easiet is to have another set you know is good,and just run them on the outside the vehicle(temporarly)to the deck and amp

 

[Motovet 10+ year member]

I'm stumped so far. The amp grounds seem good and I tried a direct ground to the HU, and no change. I can't believe the rca's are all bad as the sound comes from all three amps. I have a Zed Duece and the Profile off a distribution block with both amps grounded in different locations. Then I have the Zed Mono amp with it's own 4 guage and grounded with the Profile,(same location). I'm starting to wonder about my harness connection...maybe some funky GM Onstar thing? I am not using any of that now though. What?

 

[audiolife 5,000+ posts]

http://www.caraudio.com/forum/showthread.php?t=191860

if that doesnt work check voltage at the amps

 

[Motovet 10+ year member]

It was the POS Pioneer 880. I put in a cheap deck from my 5th wheel...and quiet as could be. Don't know what I'll do now. Thought I'd try the Pio after years of Alpines, and this leaves a bad taste in my mouth. I went through alot of sh$# to track this noise down....and it was the HU all along.......

 

[audiolife 5,000+ posts]

there is a easy fix for it if you look at jmanpc's thread i do believe

 

[Motovet 10+ year member]

The 880 has a harness lead for the RCA's though.