I don't think adding a ferrite to the cable will do much as their purpose is to clean up high frequency interference and it sounds like your problem is power supply noise. However it's an inexpensive thing to try so I'd say go for it.

Other forums have been talking about this:

USB Buffer

that they say cleans up the noise on the USB power line.

I've never heard of this company or their products, but given that the Wyrd is pretty inexpensive and they have a 15 day return policy (with 15% restocking fee) it might be worth looking in to.

Good luck.