Clicking noise on speakers after upgrade radio unit

[matthijsfh]

Hai,

I could use some help.

I tried to upgrade the stock radio (Z4, 2003) with an android auto display. All works fine, except for the sound quality. There is now a clicking noise with 4-6 Hz I hear.

Tried a lot today, even running the new unit from a battery, but the noise & clicking stays.

Can it be following:
* The new unit has 4x45 Watt power, but my car has a "hi-fi" (stock) amplifier in the back. Could it be that I now have 2 amplifiers in series?
* The new radio only has 2 RCA outputs, but I will do a test tonight to see if that helps.

* I see google results about adding "load" resistors. Is that needed?

Any ideas are welcome,
Greetings Matthijs

 

[matthijsfh]

Update...

It took me 2 days with my oscilloscope, but made great progress.

The issue: Dirt cheap Android Auto unit with poor power supply design. The WiFi chip will broadcast 10x per second. Every time that happens, during 1 msec a lot of current is needed. This makes the entire supply of the unit drop 70 mV, which the analog amplifier driving the speakers does not like.

Nearly killed the unit a dozen times, but replaced the existing capacitors by Low ESR (Low resistance) once, and added a bunch more on the 5V and 3V3 supply rails.

Issue --> GONE!! (At least I cannot hear it anymore). Noise is still there, but it's a car stereo for a car with a roof of fabric.

Anyway, happy. Although this took way too long.

Greetings Matthijs