OEM Replacement Head unit - Issue with engine sound coming through speakers

[audiA4sline]

Hi all.

Just purchased Joying single DIN unit (Chinese job) for my Audi A4 2006.

The has a BOSE amplified system.

I'm using the correct Connect2 harness kit - https://www.dynamicsounds.co.uk/audi-a4-...g-kit.html

For the audio to work, I need to patch the Orange and Black (AMP CONT) to blue cable on the connects2 harness   (AMP Remote)

The Issue -  there  is constant low popping noise when the Joying unit is powered. It's gets worse when the engine is switched on!
Basically you can hear the engine idling through the speakers. Even when the volume is low on the unit

The issue is only resolved when the  (AMP Remote) +  (AMP CONT)  connection is disconnected, but then NO sound is coming out of the speakers at all.

I have triple checks all the connections are correct and tight. I have also disconnected the amplified antenner connection.

It seems to be a ground issue (ground loop?)...however I believe  Connects2 harness has a ground input from the OEM feed from the car?

Not keen on purchasing 2 x ground loop isolators (one for each RCA pair), ideally want to find the fault.

Please could someone shed some light on what could be the fault - I have spent several hours trying to troubleshoot .

Thanks

[Trevor]

Hi Mario....welcome to the Forum

Definitely sounds like the earth provision (or lack of it) for the leads hence they are picking up EMF.

You could try relocating the leads in another area (if possible) away from any electrical interference (vehicle electrical wiring) or creating some sort of earth shielding (tin foil with a lead to earth) to eliminate any guesswork and then if it works, spend the money on the ground loop insulators.

Let us know how you get on with eliminating the interference.

Cheers,  Trevor

[audiA4sline]

Hi Trevor,

Many thanks for your message.

Connects2 have confirmed the interference is relating to a grounding issue; see their comments below..

Yes I have certainly come across this problem before. Usually on the fully amplified models and a select few platforms if that.

 But where popping sounds and feedback noise is concerned, you are correct in assuming the grounding is the issue. However not from the wire that grounds the head unit. More so from the ground shielding of the RCA connections.

 Therefore what you will require is the use of an in-line RCA ground loop isolator.

 We do a version which is the IBGLI:
http://www.connects2.co.uk/Product/ProductItem/IBGLI

Instead of going through the hassle of trial and error / the expense of ground loop isolators, I decided to swap for another harness that supports both high and low  output of head unit to supply the audio. It appears the previous harness only supported low level output. This worked first time -  http://www.connects2.co.uk/Product/ProductItem/CTSAD008.2

regards