When you tap both of the magnets of the pickup. The coil closes to brige makes a sound. The coil clpse to neck makes a sound but not as loud. And is it normal to have a slight pop when switching series to single, single to parallel. Ther is no pop single coil to series. I just recently got a used Stingray 5. I'm back in the family. After slling my 89 Stingray 5 , and 2006 limited ed Stingray 5 HS.