I have a Blaupunkt stereo in my car. I bought the Aux cable for the ipod (music plays through the cable and and charges the ipod). It works great but there is a hiss noise. I hear it even when the car is off and the noise does not change as I drive the car. It is a steady small hiss.

When I use the front 3.5 jack everything sounds great until I plug the ipod in to charge it.

Is there a way I can eliminate the hiss? I have no idea what causes it but it seems to appear when I am charging and playing the ipod at the same time. If I use a noise reducer device through the 3.5 jack it takes the hiss out. But I want to use the Ipod aux jack in the rear of the stereo and find a way to eliminate the hiss.

 

Without being there to see it,

But... Speaing as a guy who has made his LIVING fixing electronics since 1981, I'd say it sounds like you are hearing the "Switching Transients" of the charging adapter's Dc-to-Dc converter.

It may be that charging during use is just not going to work. If you had a charger with a "linear" type voltage regulator, you would not have this noise - problem is, linear type regulators are larger and generate a lot of heat internally, causing failures of the components. This is why the "switching regulator" is so popular. The disadvantage is that switching regulators are noisy - as you have observed.

So, I told you what the problem likely is, but can't come up with a solution. If it was me, I'd build a linear regulated charger with a fan in it... but then, electronics is my career and hobby!!

The only thing I can think of is to stop the noise at the source - the charger. Again, you can only do this by not charging during use OR by substituting a non-switching charger. But again, no one makes such a charger!

So there you have it, a complete answer - that does you no real good!
(During the week, this would have cost you $65).

 

Have you tried to adjust the iPod's output equalizer? It's in the "Settings" menu. Or even the "Max Volume"? Try reducing these to mid-level.

 

$65? You must be a very slow typist!

JK!

 

$90 per hour / minimum charge $65.

But you'd be disturbed to know what percentage of that $90 I see...

 

Thanks for the explaination. There is no solution to this problem because the wire charges and plays... there is no way to turn the charging off. I can use the front aux jack but I hate doing it. I played with the equalizer before but didn't find a way to solve the problem.

 

Oh, no I wouldn't! Same soup, different bowl...