True Bypass Feedback Looper Question

[seten]

Why is there a ground wire attached to pin 3 on the 3pdt?

[highwater]

You know how if you unplug the cord from your guitar, your amp starts humming and buzzing?

The same thing happens with whatever is in the loop if you just disconnect the send when the loop is off. Since the output of the loop isn't connected to anything, it's not usually an issue... but if there's a delay pedal, you could get echoes of buzz when you first turn the loop back on.

Grounding the tip of the send jack when the loop is bypassed stops that from happening.