I had wrote this part for those other than the OP, but deleted it for the sake of diplomacy. The more I thought about it the more I think it’s something to include because it ties in and is something that gets lost among the electric guitar community. Also, when a comment is made that everything uses switched mode power supplies and there is never any issues is very misleading. If you don’t believe open up your computer case or if it has a clear plastic window that’s usually all it takes and bring your plugged in guitar towards the computer and tell me what happens.

Here’s the original comment:

This is for all and any other guitarist who might be reading this. The crazy thing about an electric guitar with electro magnetic pickups, metal strings (wires) connected to another electronic device with a cable, is that if the ground is poorly connected or more than one path to ground with different impedance reference planes is created what essentially is devised is a giant antenna just asking for stray RFI and EMI to come make friends with the signal.