I can run all the electronics through a 1000w isolation transformer and I can lift the ground to the transformer and I still get the hum with no noticeable hum reduction. I thought isolation transformers were supposed to eliminate ground issues.
However, I ran a 50’ power cord from across the house to another outlet and it reduced the hum at least 50%. So it appears the house electricity is causing the issue in some circuits.
However, I ran a 50’ power cord from across the house to another outlet and it reduced the hum at least 50%. So it appears the house electricity is causing the issue in some circuits.