77Views2Replies

Author Options:

Why is my ipod creating parasitic signals on the speakers? Answered

I'm currently trying to build an ipod dock out of these speakers (http://www.netbooks-umts.de/lautsprecher-hamma-sonic-mobil-80,305.html — they use an usb plug as alimentation) and since i'd like my station to be able to charge the ipod, I decided to use a double usb charger: http://www.agelectronique.fr/ag/p_produits.php?cat=5&sous_cat=60&ref=85-8984

When and only when both speakers and ipod are connected to the charger and the speakers' jack is connected to the ipod, I get a parasitic signal on the speakers. I tried all the other configuration (using one or two power sources, using a different audio input), but none present the same issue.

Would you know why I have this problem ? Do you know how I could solve it ?

Discussions

0
None
jmorel

8 years ago

Thank you for the very quick response. I read the document, and it looks like one solution could be to re-wire the circuit so that ground distribution is made along a star topology. I'll do that and see if it changes anything (I hope so). But if it doesn't, is there an other way to solve this issue (knowing that I can't open my ipod and that I'd rather leave the charger untouched) ?

0
None
Re-design

8 years ago

Connecting the speakers to the ipod with the jack then connecting both of them to the same charger is creating something similar to a ground loop.

Read the first paragraph of this article.