Try a different interconnect and see if it still does it.
3 responses Add your response
Your problem could be the interconnects, (most likely a broken internal shield connection) or a ground loop has formed between your pieces of eqiupment. A ground loop is a differance in potential between equipment grounds. The culprit is usually cable TV or sattelite hooked up to your preamp or processor. Totally disconnect it from your system and TV. If the buzz or hum is still present, disconnect one piece of equipment at a time from your preamp or proccessor, if still present disconnect your preamp from your amp. This will leave you with just your amp and speakers. If the noise is still present chances are you have develope a faulty power supply filtering capacitor.
If you find that the cable or sattelite is causing your problem, you will need to ensure that you ground the cable to the same potential that your home is grounded to (Main AC Pannel), or ground rod or main water pipe supply.
You can also play around with cheater plugs bought at your local hardware store, what you will do is float the ground on the power cord of each piece of equipment this will also help you find the piece of equipment the noise is coming from.
Once again your problems will be 1) Bad interconnect, 2) ground loop, 3) Bad capacitor in side power supply.
You practice of disconnecting and connecting equipment with your equipment power on is highly not recommended but doubtfull that it caused your problem.