Okay, this is probably been asked before but I can't find it in a search as I don't really know what to call these types of jacks. How do I tell what positive and negative are on these strange things??
The Tip Switched terminal could be, should be grounded so that when you unplug the input jack, the input is grounded instead of left wide open to pick up hum & radio stations. Also very useful for troubleshooting noise issues.