I have an Ibanez SG300 active bass and a Fender Rumble 75 amp. When connected at home, there is a constant hiss emanating from the amp. Especially bad when adjusting highs on pre-amp guitar. I visited the store where puchased and plugged in bass/amp. Perfect! Quiet. They suggested that maybe I have a grounding loop issue at home that produces the problem. I purchased a Hum X hum exterminator from EBTech per the store suggestion. I plugged in at home, same issue. Hiss and buzz. Is there a problem with my house wiring? There are no flourescent lighting and the grounded plug is on an outside wall. Do I need to call in an electrician? Any suggestions will be greatly appreciated.