Have a problem with DIY WiFi radio .

supercool

New Member
Hello, I am building a mono, internet enabled, WiFi radio and I have a problem.

I am running into what I believe may be a grounding issue. When I turn the system on, I hear all kinds of noise coming from both my computer component and my WiFi dongle.

I know that the WiFi dongle is contributing to the noise because if I remove it, some of the noise is gone.
If, I use a completely different sound source, such as a battery powered MP3 player, I get very little noise.
I am thinking I may need a ground loop isolator, but curious as to whether anyone else has suggestions.
Here is a diagram of my circuit (sorry it's a bit crude) NOTE: I am providing extra power to the USB hub because I do not believe the computer (it's a pogoplug) can output enough power over a single USB.
cTyCB.jpg

I am using Zaph's filter (as my receiver is a HiVi B3N)
ZWS7G.gif

And I am using a stereo to mono summing box here:
ujnr4.gif

Finally, I am using this step-down transformer(LM2596S).

I found this question and think it may discuss a related problem, but I am not sure how I should proceed to fix my issue.

I have tried the following layout with the raspberry pi and notice the same noise problem. Also solved by using two seperate AC/DC adapters.
1PAwG.jpg
 
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