Hi,

Good detective work, but yikes, you can't use unshielded 16-gauge wire for any low-level connection!! No wonder it's picking up hum. When you explained, I thought, "how unusual that shielded cable is still picking up AC fields" but now it's clear.

You must use shielded cable for all but speaker (high-level) connections.

Regards,

Alan Lofft,
Axiom Resident Expert (Retired)