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.
I am using Zaph's filter (as my receiver is a HiVi B3N)
And I am using a stereo to mono summing box here:
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.
UPDATE: 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.