Hello. Wondering if someone has any experience with this situation. I have a '66 vibro champ that has a hum that is only bothersome when I take my fingers off the strings. It is improved somewhat by my HumDebugger. It has the original 2 prong power cord. Would putting a grounded 3 prong cord change this hum, possibly eliminating it? Could it make it worse? Thanks for your input!