I'm building a USB soundcard with a PCM2702. I have built the thing on a breadbord to test it. It sounds pretty good, but when I unplug the USB connector from my laptop or when I turn off my computer I hear a very anoying noise.
This is very anoying because I have my headphones on when I turn off my laptop.
How can I get rid of this noise?
Do you have any other advise for my project?
This is very anoying because I have my headphones on when I turn off my laptop.
How can I get rid of this noise?
Do you have any other advise for my project?
Attachments
Perhaps putting a inductor on the Vbus line? It could be some voltage fluctation when you pull out your plug.
http://www6.head-fi.org/forums/showthread.php?t=105088
http://www6.head-fi.org/forums/showthread.php?t=109671
Ask them if they hear any noise, because they have a inductor on that Vbus
http://www6.head-fi.org/forums/showthread.php?t=105088
http://www6.head-fi.org/forums/showthread.php?t=109671
Ask them if they hear any noise, because they have a inductor on that Vbus
I placed a 100uF capacitor between Vbus and GND. With the USB output resistance, it functions as a low pass filter.
The off noise is fully eliminated, but there is still a small on noise. I think the on noise is now produced by the charging of the 100uF capacitor. I will try a smaller capacitor.
I will also try a coil in the Vbus line. That functions as a low pass filter too, but maybe it works better.
The off noise is fully eliminated, but there is still a small on noise. I think the on noise is now produced by the charging of the 100uF capacitor. I will try a smaller capacitor.
I will also try a coil in the Vbus line. That functions as a low pass filter too, but maybe it works better.
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