Hum/whine issues with HD Audio adapter

So, I had been using the audio adapter in one of my vehicles as an FM adapter, and just moved it to a different vehicle that has an AUX input that I can use the headphone connector for.

The issue I’m running into is that I have a very high pitched whine that changes pitch with engine speed.
It’s pretty annoying.
I tried plugging power in via the ZUS charger as well as via a different 12v USB adapter, with the same results.

Has anyone else dealt with this, and maybe have any ideas of how to fix it?

Hey @nated

Run me the set up again.
You are plugging in your 3.5mm from the UHCAA to your Aux input on your deck and the USB port from UHCAA to your ZUS Charger input?

High pitch sound that changes pitch with your engine, is actually a pretty accurate description.
What you have here is your ground loop in audible format.

You’re alternator speed changes so does the current/amps which is what you are hearing.
Try a different power source and your issue will vanish.

You have a car with bad grounding for their wires. It isn’t unheard of, it’s just not experienced as much by most drivers since not everyone has FM transmitter these days.

Change your power source to something else, preferably that isn’t connected to your !2V battery directly (assuming its a standard 12v car).

Hope this helps :slight_smile:

Hi @Shak!
Yeah, it’s connected exactly as you describe.

Now that you say ground loop, that’s exactly what it is… I remember that from back in the reaaally old-school car days, but I didn’t know it was still a “thing”. I figured newer cars would have fixed their grounding troubles. Guess not!

I’m actually not using the FM transmitter function at all since I’m using the AUX jack. The sound is quite a bit better now that I can go in direct.

Thanks for reminding me what the problem is! I’ll see if a cheap ground loop isolator takes care of it.

Great! :smiley:
Glad to be of service!

and yeah, it is really old school, but technically so is Aux, since that’s analog audio. Before you grab the isolator, just double check. Since FM Transmitter is digital, if you don’t get any feedback when using the FM Transmitter, then it would confirm the grounding issue. Just to be sure.


Yeah, I didn’t get any using the FM transmitter, so that’s definitely what it is.

It’s my “new” camping vehicle… just old enough that it has bluetooth built into the head unit, but only for calls, not for music. So even though it’s 10 years newer than the vehicle I was using before, the HD Audio adapter is still coming in handy!

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Nice! :smiley:

By the way, I picked up a ground loop isolator for $9 off amazon, and that completely fixed the problem.

Thanks again!

@nated ~ Nice & you’re welcome! What was it called on amazon? I might pick one up too lol

Here you go!

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Cool. Thanks, I was looking at another one (can’t even find the link anymore) for $15 but $9 bucks is better! MPow also make good stuff.

Definitely will grab this.
Thank you!