Well done, Steve. I've been fighting an annoying hum for quite awhile now. No one ever explained the problem or suggested the solution more clearly than you did. Thanks. I'll give it a try.
What is causing the hum?
I hooked up my MC-12 to my Sherbourn amps for the first time last night. I noticed a very annoying hum and also, it seemed like I was not getting all of the power I needed to my Thiel Powerpoints. With the volume all the way up, the powerpoints were not overly loud. I would expect them to be, as the Sherbourns are 200watt amps at 8 ohms. Heck, my Yamaha receiver made the Thiels extremely loud at 50% on the volume control.
What gives? How do I get rid of this hum?
What gives? How do I get rid of this hum?