I just had a McIntosh C32 refurbished by McIntosh. My entire system is electrically connected through a line conditioner. When I hooked up the C32, an annoying hum began emanating from my speakers. I live in an old building (1892) so there are not any grounded outlets and I'm assuming the breaker box isn't grounded either. Are there any other solutions for a grounding hum? Could there be something else wrong even though this did not occur with the previously installed pre-amp? Regards, David