You may want to try this before you spend much $$$.
I had a sporadic hum that I thought was in the AC line. I ran a new AC outlet back to the circuit breaker but it didn't cure it. I discovered the cause by accident when I disconnected the cable wire from the back of my TV and from the wall to rearrange some wires. The hum disappeared completely.
It comes back every few months but I just disconnect the cable line and reattach. It must build up a charge over time. Worth a try.
I had a sporadic hum that I thought was in the AC line. I ran a new AC outlet back to the circuit breaker but it didn't cure it. I discovered the cause by accident when I disconnected the cable wire from the back of my TV and from the wall to rearrange some wires. The hum disappeared completely.
It comes back every few months but I just disconnect the cable line and reattach. It must build up a charge over time. Worth a try.