@jmcgrogan2 wrote:
This happens due to a different grounding point. I discovered this at my house also, but with DSS/DirectTV back in the early days. I had the dish and coax grounded outside right below the dish with a separate copper grounding rod, and the electrical service in the house was grounded 35 feet away, at the service entrance. I didn’t realize it at the time, but those two different grounding points are a difference in potential, as well as creating a 35 foot "loop" if the ground from the satellite were somehow introduced into the audio system (which is what was happening with the DirecTV receiver). When I unplugged the satellite coax, the humming went away.
While this doesn’t quite apply in the case of the OP’s question, it makes me wonder what the grounding situation is for the wiring in the house. If everything is grounded through the circuit breaker panel (which in turn is grounded to a single point in the house such as a water pipe, or outdoors to a stake in the ground), then it should be OK. But if somehow the newer wiring is grounded in a separate place, then that could cause a problem.
I have an odd hum issue in this house as well. My equipment is in an addition built in the mid 1980s, where the original part of the house was built in 1940. I found out that the ground wire isn’t connected in some of the outlets in the addition, so I have my own dilemma to attend to shortly...
Disconnect any CATV hookup regardless, you may be surprised.
I fought a ground loop hum for a month or so, and ignored the CATV line because it was on a different circuit. Turned out to be the culprit anyway.
Ground loops find a way.
This happens due to a different grounding point. I discovered this at my house also, but with DSS/DirectTV back in the early days. I had the dish and coax grounded outside right below the dish with a separate copper grounding rod, and the electrical service in the house was grounded 35 feet away, at the service entrance. I didn’t realize it at the time, but those two different grounding points are a difference in potential, as well as creating a 35 foot "loop" if the ground from the satellite were somehow introduced into the audio system (which is what was happening with the DirecTV receiver). When I unplugged the satellite coax, the humming went away.
While this doesn’t quite apply in the case of the OP’s question, it makes me wonder what the grounding situation is for the wiring in the house. If everything is grounded through the circuit breaker panel (which in turn is grounded to a single point in the house such as a water pipe, or outdoors to a stake in the ground), then it should be OK. But if somehow the newer wiring is grounded in a separate place, then that could cause a problem.
I have an odd hum issue in this house as well. My equipment is in an addition built in the mid 1980s, where the original part of the house was built in 1940. I found out that the ground wire isn’t connected in some of the outlets in the addition, so I have my own dilemma to attend to shortly...