Alternator A/C voltage question

[Bmwe5320023.0]

Brand new alternator, brand new amp, SAME OLD WHINE.

[80stech]

If you want to DIY then why not make your own cables? Foil shield is better than braided, twisted pair with the shield grounded at the source (but you could try at both ends as well)

[Bmwe5320023.0]

Originally Posted by 80stech

If you want to DIY then why not make your own cables? Foil shield is better than braided, twisted pair with the shield grounded at the source (but you could try at both ends as well)

I do not want to DIY anytning at this point lol!!
Make rca cables? Why not?
I dont know, it's another variable that I can screw up...
Are we at a point in 2022 that DIY rca cables would be better than what's commercially available from professional audio stores etc? In an industry that developed and matured over decades
I've been trying to get this fixed for more than a year, I just want it to work. I don't really want to learn how to fabricate audio cables at this point lol. I don't even know if rca cables are the issue at all

[wpoll]

Might be worth testing to see if the whine is in the audio leaving the source (H/U)....

And/or try powering the amp from a separate (spare) car battery, just as a test.

[Bmwe5320023.0]

Originally Posted by wpoll

Might be worth testing to see if the whine is in the audio leaving the source (H/U)....

And/or try powering the amp from a separate (spare) car battery, just as a test.

It's my second head unit.
I can try powering the amp with another battery, though I don't have one, but this is my 3rd amp

[eskirvin]

This whole thread just hurts. So much money spent for a good experience that the user certainly isn't getting, from his perspective.

A number of people in various threads on too many forums to count, install stereos from trusted brands only to find out they've got grave design flaws. So much is designed by these companies and sent to China to produce. I don't know if these companies QC it afterwards, but it sure seems many don't.

Try grounding the negative lead of your RCA cables to the same ground your device is connected to. For the source, ground those leads at the same point the source unit's power is grounded. For the amp, ground them where the amp is grounded. Do it for the source first, check if the whine is reduced or gone. Do it for the amp, check if the whine is gone or reduced, and then try it for both at the same time and see if the whine is reduced further, or gone. If any of these steps you've taken temporarily works, make them permanent.

You can't build your own radio, so bandaid solutions may be all you can commit to. If it gives you the sound you desire, make it permanent. I've got an Xtron Android head unit in my E53 and the whine was initially awful until I committed to grounding the negative of the RCA output leads to the same ground as the head unit. The whine is only noticeable now if there's no music playing and I'm at a stop allowing me to rev the engine.

Also, I don't remember reading it in this thread, but if you used the "stock" ground for your head unit, I'd suggest making your own.

[Bmwe5320023.0]

Thanks for your support buddy!

If you think this thread hurts, take a look at these

https://www.diymobileaudio.com/threa....448099/page-7

https://audiosciencereview.com/forum...4#post-1233123

I'm just trying to stay positive

I'm on my third amp, so i doubt it's the problem lol
I think I already tried grounding all rca ports on the headunit together and grounding them to rca cables.

Right now I ran an extra ground cables from the headunit back to the trunk, and grounded it at the same stud where the amp is grounded
I guess as per your suggestion, I can just connect one rca cable out of 4, and ground the outside of that rca cable where it plugs into headunit and into the amp?
It's a bit tricky attaching wires to the outside of the rca cables lead.

So I'll try grounding rca cable to the ground to amp/headunit and see if it changes anything.
Thanks your your suggestion

[AV8R4AA]

Sometimes when my wife or teenagers are in the car I hear the same noise.
It’s a high pitched noise that I know is either going to make me mad, or cost money.

[Bmwe5320023.0]

some hood humor is in due course for this thread

[Bmwe5320023.0]

I got the tech working for 5 hours on the vehicle right now lol. When he showed up and saw the alternator and rpm make the whine, he said the new alternator is bad and I need to replace it. He said he had cases when the brand new oem alternator was making noise, and aftermarket rebuilt alternator fixed the issue. I said ok, how are you testing it to condemn the alternator lol? He doesn't have an oscilloscope. Like for real, both alternators bad and even with Newmar amp filter??
He tried a different amp, different speaker, all the same results.
Thankfully there's a loud static noise when the ignition is on, without starting the car. So that rules out the alternator...

Basically it looks like there's some kind of a short somewhere. We tried powering the system without turning key to on, and it doesn't make any sound.
There's some short somewhere for sure.
We tested resistance between headunit and metal bar under the dash, it's 0.
Then it I turn the key to "ON", that resistance jumps to 30 omnhs. Gotta find that short.
Some component that is activated by the ignition is grounding onto the vehicle ground. With higher rpm more amperage gets sent to the ground, and the ground loop gets worse.
That's my theory for now. Gotta look for that short with ignition on

When I turn the ignition is