Wayne Parham Messages: 18789 Registered: January 2001
Illuminati (33rd Degree)
One thing to consider is the possibility of a ground loop when a television connected to cable TV is connected to your sound system. This can also happen if you connect cable into your Hi-Fi tuner. Using a 300 ohm transformer will isolate cable ground from your sound system's ground. Many times earth ground on the house current circuit is nowhere near cable ground so if they aren't isolated, a ground loop exists. You can reduce hum considerably by isolating these.