Engine whine only when plug in sub's RCA..?

[CJL 10+ year member]

Pioneer HU, Got a 4 ch amp running comps on 1+2 ch and 2 12's bridged on 3+4 ch,with 2 sets of rcas.

I get engine noise when I plug the rca going to ch 3&4.

I switched the rca from 1&2 with 3&4 to see if rcas was the culprit but still had noise from ch 3&4.

Click to read more...

 

[5.3bowtie 10+ year member]

How do you have engine noise through subs?? Do you not have the lp filter on??

 

[fasfocus00 5,000+ posts]

sounds like your amp has bad grounding for the RCA inputs on those channels.

 

[mk_ 10+ year member]

Possible bad pico fuse, with pioneer head unit. Try grounding the RCAs at the back of the head unit.

 

[Blue Fury 10+ year member]

So the PICO fuse discriminates against the 3&4 channels only huh?

No.

 

[CJL 10+ year member]

How do you have engine noise through subs?? Do you not have the lp filter on??

No I can hear it through my comps.

sounds like your amp has bad grounding for the RCA inputs on those channels.

Easy fix?

Possible bad pico fuse, with pioneer head unit. Try grounding the RCAs at the back of the head unit.

Did that.

 

[thorshammer1 10+ year member]

Take your hu ground and run it directly to the 4 channel ground. It should eliminate at least half if not all.

 

[CJL 10+ year member]

Take your hu ground and run it directly to the 4 channel ground. It should eliminate at least half if not all.

I heard of that before,but it sounded weird to have a 5-6' HU ground. Is that a common thing? Ill try this today.

 

[CJL 10+ year member]

Ok tried that,and still have noise on the subs channel.

 

[thorshammer1 10+ year member]

Did it help with the noise on the high side?

Does your hu have 3 pre outs? try the rear channel set as the sub out?

 

[mk_ 10+ year member]

So the PICO fuse discriminates against the 3&4 channels only huh?
No.

The gentleman is looking for suggestions and I gave him one. Chill out

 

[CJL 10+ year member]

Did it help with the noise on the high side?
Does your hu have 3 pre outs? try the rear channel set as the sub out?

Didnt help nothing.?

Yes it has 3,but even when I plug it into the rear's RCA output I still have noise.

I was able to get rid of the noise though. I ran a short run of RCA from the amps output to the input of amp's ch 3&4.

Would that mean the problem is within the HU? Why would only the sub and rear output of the HU cause noise?

 

[fasfocus00 5,000+ posts]

Didnt help nothing.?
Yes it has 3,but even when I plug it into the rear's RCA output I still have noise.

I was able to get rid of the noise though. I ran a short run of RCA from the amps output to the input of amp's ch 3&4.

Would that mean the problem is within the HU? Why would only the sub and rear output of the HU cause noise?

so you ran a different set of RCAs and it corrected the issue? than you issue with the RCAs that are currently there.

 

[CJL 10+ year member]

Not really a different set,just bypassed the HU's rear & sub preout.

I switched the Front's rca with the sub's rca and I still had whine,so I dont believe the rcas is the problem.

 

[fasfocus00 5,000+ posts]

Not really a different set,just bypassed the HU's rear & sub preout.
I switched the Front's rca with the sub's rca and I still had whine,so I dont believe the rcas is the problem.

I'm experiencing ground loop issues with mine, I've done everything but uninstall everything and reinstall. I've seen some simple things sold problems before. It really can't hurt anything to try, especially b/c it's picking interference from some where and RCAs are known for doing that.