This annoying whine

[Dbld54]

Hi, I needed Assistance troubleshooting an annoying whine coming out of my speakers.
I think it started when my ground point in the trunk, became loose and I had to try different areas but not too sure.

I have two amps, I've disconnected the subwoofer amp to try and keep it simple.
This leaves the 4 channel amp.
Clues:
The sound does not get louder when I increase the volume.
It is present even with volume at level 0 on the HU.
If i disconnect the 4 rcas the whine is gone. If I connect any rca cable to any of the Jacks the whine returns. Even if it's just 1 rca, that one speaker will whine.
I've tried several ground points, the latest is using an existing ground from the stock Ford wiring.
The ground points are sanded and tightly connected.
Amp fuses are fine.

Please let me know if you have any ideas.
Thanks

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[Jimi77 5,000+ posts]

Thanks for the reply, 2 questions:
which of the two options below? and does it effect SQ?

Amazon product ASIN B0763HW31Y
Amazon product ASIN B07S8VKG99

The ground loop isolator - the top one. It might effect SQ if it's poor quality.

 

[Dbld54]

Why not try a ground loop isolator on the 4 channe

The ground loop isolator - the top one. It might effect SQ if it's poor quality

I've now bought two 2-channel isolators off amazon.
Next day delivery so i'll share the results tomorrow.

 

[Jimi77 5,000+ posts]

I've now bought two 2-channel isolators off amazon.
Next day delivery so i'll share the results tomorrow.

Good luck

 

[Dbld54]

Good luck

The ground loop isolator resolved the constant whine, and whine from power windows and accelerating.
Unfortunately, a loud popping sound is present when
-starting the car/turning off the car
-changing stations
-changing the volume from 0 to 1 and 1 to 0.

I did discover that when i disconnect the rear RCAs at the amp, the popping stops.
I tried a different set of RCA cables from the HU rear to Amp rear, issue continued.

Since it's not the RCA cable, i suppose it's related to the RCA jack which i replaced already.
And i tried another amp, without the popping present so it can't be the HU.

What do you think Jimi77 ?

 

[audiobaun 5,000+ posts]

 

[audiobaun 5,000+ posts]

 

[Jimi77 5,000+ posts]

The ground loop isolator resolved the constant whine, and whine from power windows and accelerating.
Unfortunately, a loud popping sound is present when
-starting the car/turning off the car
-changing stations
-changing the volume from 0 to 1 and 1 to 0.

I did discover that when i disconnect the rear RCAs at the amp, the popping stops.
I tried a different set of RCA cables from the HU rear to Amp rear, issue continued.

Since it's not the RCA cable, i suppose it's related to the RCA jack which i replaced already.
And i tried another amp, without the popping present so it can't be the HU.

What do you think Jimi77 ?

0-1 volume change isn't uncommon; is it really loud? How did you set the gains? I'd double check your soldering job on the repaired RCA jack. Try grounding the RCA jacket at the amp.

 

[Dbld54]

0-1 volume change isn't uncommon; is it really loud? How did you set the gains? I'd double check your soldering job on the repaired RCA jack. Try grounding the RCA jacket at the amp.

Thanks for the suggestions, It's loud enough that it can't be ignored, it'll make someone jump a bit.
I just tried a speaker wire, wrapped around the rear RCA jacks on the amp and grounded the other end.
No difference at all, popping is present. The popping was also present before i replaced the RCA jack.

I'll take another look today, but assuming the soldering is fine, nothing is burnt on the board and everything is tight... it looks like we've exhausted all options, and i'll need to replace the amp.

 

[Jimi77 5,000+ posts]

Thanks for the suggestions, It's loud enough that it can't be ignored, it'll make someone jump a bit.
I just tried a speaker wire, wrapped around the rear RCA jacks on the amp and grounded the other end.
No difference at all, popping is present. The popping was also present before i replaced the RCA jack.

I'll take another look today, but assuming the soldering is fine, nothing is burnt on the board and everything is tight... it looks like we've exhausted all options, and i'll need to replace the amp.

Actually, I think the pop is coming from the HU. Can you try swapping the front and rear RCAs and see what happens? Have you tried hooking up another source (like a phone) to see if you get any popping?

 

[Dbld54]

Actually, I think the pop is coming from the HU. Can you try swapping the front and rear RCAs and see what happens? Have you tried hooking up another source (like a phone) to see if you get any popping?

Popping was still present after swapping the front and rear RCAs at the amp.
Another source, like my cell phone connected to BT, also had the popping.

How can it be the HU when the popping and whine disappeared with another 4-channel amp connected?

 

[Jimi77 5,000+ posts]

Popping was still present after swapping the front and rear RCAs at the amp.
Another source, like my cell phone connected to BT, also had the popping.

How can it be the HU when the popping and whine disappeared with another 4-channel amp connected?

I'm talking about a phone connected to the amp via the RCA inputs.

If the popping disappeared with another amp, then you've narrowed it down to the amp.

 

[Dbld54]

m talking about a phone connected to the amp via the RCA inputs.

If the popping disappeared with another amp, then you've narrowed it down to the amp.

My apologies, i reconnected the borrowed 4 channel amp, there is no whine once all connected, but the popping is still present, just quieter. Maybe the gain is down on this amp, i didn't check.

The same scenario is present with this borrowed amp: unplug the Rear RCA cables to stop the popping.
Does that mean the problem is the Rear RCA adaptor on the HU?

 

[Jimi77 5,000+ posts]

I think it's probably the HU. How were the gains set; did you follow one of the methods in the link below?

Gain Settings

 

[Dbld54]

I bought a new 4 channel amp last night, i don't want to bring down the SQ using the ground loop isolators. This should resolve the whine as confirmed with the borrowed amp.

Popping: with the gains at 0-1% there is a quiet popping, and increases in loudness as i increased the gains. Both 4-channel amps do it. Must be the headunit? Edited later, yes it was the HU.

 

[Dbld54]

Almost at a perfect finish line. I bought a new HU and amp which solved almost all problems.
When the car is running, and the radio/bluetooth playing, there is a slight whine.
It can be reproduced when using the power windows and when accelerating which is where it's most present.

Could it be because i don't have a negative 4awg wire from the battery to frame? I added a HU ground to frame..no help. I also included pics of my current ground point in the trunk for the two amps, one 4awg and one 8awg piggybacking an existing ground location.
I understand a ground loop isolator might help but keeping as last resort, I'd prefer to solve the issue since it wasn't present before.
RCA filter i dont like due to SQ degradation.

What do you think?