@dzfam02, I've had this same exact problem. In my situation I wasn't using "Jam", I was using a different wireless mic, but everything you describe was the same for me.
Because I have an extensive history in the "old-school" systems (i.e. analog), as soon as I heard the hum I knew what it was. It's almost always a cable of some kind allowing RF noise, or some other form of noise, into your system. Usually, all you have to do is move around your cables, power bricks, lamp cords, or ANY other cable that has current running through it. For me, it was a simple move of one cable just 6 inches to solve the problem. I have seen it take some rather drastic rearrangements to eliminate the hum. Consider moving you computer around as well. I have always found it strange that the introduction of a new piece of equipment can cause a situation where a seemingly non-related cable and/or equipment must be moved to eliminate the hum that was a result of the new equipment being brought in.
Things to live by:
ALWAYS use high quality shielded cables. NEVER lay too many cables too close together. NEVER use gender changers to connect 2 shorter cables to make a longer one as the connection ALWAYS leaks signal AND allows offending signals (hum?) to be introduced. Instead, use 1 continuous cable.
Hope this helps...