(probably) silly grounding question, FX loop

[Godwin]

Hello.

I'm building a looper with a bypass function, which is rackmounted (footswitchable), to run in the FXloop of an amp.

i was thinking, seeing as i know very little about grounding, that i could just connect the ground from the amp send directly to the ground on the amp return, separating it from the complex network of stuff inside, thereby eliminating any grounding issues or hum from the looper itself, or any effects connected to it. assuming the amp, looper, and effect units are all plugged into the same mains circuit, there shouldn't be any voltage difference on the 0v, meaning the signal wouldn't be "damaged" by a ground loop.

also, would this remove the need to ground all the inputs/outputs not in use?

if I'm talking rubbish,please just say.
thanks in advance, any help or advice will be much appreciated.

[R.G.]

If you wire it that way, it will hum unendurably. The signal grounds between amp and effects must be made in a manner that is NOT the AC safety ground.

All the signal grounds must be connected together.

[Godwin]

thanks R.G.
um, i didn't think i was suggesting grounding anything to the ac safety ground (the mains earth, right? the 3rd pin from the wall?) except the metal parts of the chassis, which i have read ought to be insulated from the signal in/out jacks.

is that right, or am i just getting everything mixed up?

I have literally built this power supply, and was planning to ground everything to the 0v output at the bottom right. as the construction is mainly wood, except for a 1U faceplate.

should the signal ground be separated from the DC ground? if so, how?

thanks for your help