Re: Complete the DC circuit?
My knowledge of wiring in the US is limited.
So FWIW …. If you use a 3 wire extension cord and the earth is disconnected (broken or cut off) at the plug end, what happens is that the active and neutral act like they are connected by two series capacitors with earth wire connect in the middle dividing the voltage in about half. Because the earth wire is connected at the plug end, and hence the metal part of your equipment you will get a shock.
The current will be limited by the amount of capacitive coupling … and you will need an earth return such as the strings on your guitar. (the strings are connected to earth via the amp which is plugged into an earthed socket at the stage end)
I would suggest you measure the voltage with an AC meter connected from the mic body to an earth somewhere. If you see about half of your normal AC voltage, chances are something like this is happening.
Peter
