Is there any way to have an active, switch-on magnetic circuit under the pickup? The idea is that the pickups are single coil, passive and unaffected until the circuit is engaged. When engaged, it creates an opposite-polarity magnetic field, eliminating the 60-cycle hum of a solo'd pickup. I will probably have an answer for myself by the morning e_e but I would be most interested and grateful of anyone's suggestions or resource tips.. I am kind of going to use some relay switch coil stuff I have as a jumping off point. Thanks!