Ground loop(s) issue with bluetooth system.

[datguy.dev]

Greetings,

So this is what I'm working with: http://www.caraudio.com/forums/car-audio-build-logs-cars-trucks-suvs/635804-budget-friendly-ford-escort-system-tablet-components-10-sub.html Currently, there are some ground loop issues goin' on.

For a desc. of the noises. With the volume at 1, there is a hiss. In the hiss you can hear car related sounds like the beeping if you happen to leaves to lights on or key in the ignition. With the volume from say 1-50 I get bad engine whine. I drive a manual car and the engine is very obvious with it's sounds. Low idle produces a popping sound from the speakers every time it fires! Like a machine gun going off at higher volumes. Of course I have whining as the RPM changes as well. At higher volumes, like near max, the noises are hardly notable.

I overnighted a ground loop isolater for temporarily relief. However, it failed to produce any different results. I tried it installed on the RCAs of the bluetooth receiver, the root audio source, before the front amp, before the sub amp. Then I tried all that with other RCAS disconnected in an attempt to find the noisy device. I got nothing from my testing. Side note, my RCAs for the sub amp are ran on the opposite side of the car than the power for the amp. The bluetooth receiver sits near the front amp, so the RCA cables there are short and direct.

I know the next step is to increase the quality of my grounds; all around. The problem I have there is my engine grounds are basically inaccessible. Such as even the alternator is impossible to reach without removing engine components. (

) Therefore, I'd rather pay an audio shop to fix it if that was the only solution(s). Note, I did not have this issue before installing the tablet and bluetooth receiver. Is the receiver just a piece of garbage? I was curious if anyone had any suggestions?

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[Jeffro83]

If you do a Google search it should show videos of how to ground the RCA jacks themselves sometimes that seems to help clear it up but most likely if the problem started when you added the new head unit I would try running a temporary wire from the ground on the head unit 2 a few different ground points and see if that clears it up might get you nowhere might help you out even if you just run a temporary jump wire from the head unit straight to the negative terminal on the battery at least then you'll know what the problem is those are my two suggestions for now

 

[datguy.dev]

If you do a Google search it should show videos of how to ground the RCA jacks themselves sometimes that seems to help clear it up but most likely if the problem started when you added the new head unit I would try running a temporary wire from the ground on the head unit 2 a few different ground points and see if that clears it up might get you nowhere might help you out even if you just run a temporary jump wire from the head unit straight to the negative terminal on the battery at least then you'll know what the problem is those are my two suggestions for now

Will do. I'm down to troubleshoot to find the source of this much noise. It's quite a lot. If you'd be patient with me while I'm currently on mandatory overtime. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif there are a lot of testing points. Such as when you say "headunit" do you mean the tablet and or it's chagrining circuit, or the bluetooth receiver? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I need to also listen to the tablet with headphones, while charging and not, to make sure that signal is clean before suspecting other sources.

 

[Jeffro83]

It's all good man just post back after you've had a chance to troubleshoot that is a good idea about listening to the tablet but being as the headphones will be coming from the headphone jack it's unlikely that you will hear the the noise in the headphones although depending on how you are charging it it could be causing a lot of feedback to get into your tablet so it's definitely a good idea if you do hear the noise through the headphones try charging your tablet straight off the cigarette lighter or disconnecting it from the charging source and see if the noise continues if it does then it's probably an issue with the tablet as far as the grounding goes on the RCA jack start where your first RCA connection is in work your way back to the amps from there I've seen it work on the head unit side of the RCA jacks and other times on the amp side when I was talking about grounding the head unit at a different Source I was thinking of a normal CD player or double DIN and just using the ground wire most likely depending on how your stuff is set up it would be the ground wire for the charging of the tablet if you have it hardwired or the ground wire from the device you're getting your RCA signal from don't really have a lot of experience with set ups like yours but other people on here do and sometimes you might have to be a little persistent in asking but eventually somebody will be on here that can help you out but I'm down to share my knowledge like I said just hit me back after you've had a chance to test some of that out I work a lot too so if I don't post right away it's because I'm at work and I will as soon as I can

 

[datguy.dev]

I never did find the source of the noise(s). I checked the integrity of grounds. I grounded just about any negatives I could find. One after the other, there was no difference at all regardless of what was grounded.

So all I can assume is the iSuck BT receiver ... well *****. I pulled it and ran a 3.5mm headphone to RCA split to each amp. So there is no more noise. Actually, it is better this way because every time paired, the iSuck BT module made an awful loud beep sound for the connection and there is no more delay to start playing music.

 

[marc2112 10+ year member]

Do the big 3 upgrade. Your car is nearly 20 yo so I would not be surprised if all your oem ground wires are corroded to death.