Going Topless

What about using a sheet of kitchen aluminum foil for a top cover? I have been told that this blocks RFI and EMF (electro magnetic?) and at one time used it between an amps external power supply and my CD player which were cramped togther.

Your reference to eddy currents reminds me Frank of a traumatic event that I have not been able to explain. I had on loan an amplification chain -Spectral dmc12 and McCormack DNA1- and a pair of MIT330 interconnects. One of the MIT RCAs was defective and I could not use them so I placed them on top of the pre. One day as I was changing a CD I moved my hand over the interconnect. I did not touch it and it was not connected to the sysrem anyway. There was a loud brief ugly sound and two tweeters and a woofer died on the spot. I suspected some kind of magnetic field like when you change the reception of a radio by moving in the room. I have no idea what is inside the famous MIT boxes. Supposedly the dealer spoke with MIT and they repaired my speakers free of charge. However I was never given an explanation. Anyone knows what happened? Sorry for straying from the topic.

Pefstratiou it seems the you may have been the victim of a stray static electric charge induced from your body into the equipment as your hand passed over the cable's insulator? It may or may not have had anything to do with that cable, so I think you were incredibly lucky to have the damaged drivers repaired at no charge. But then again MIT is like that: very customer-supportive I've found. One day when I called them (& no one else was avaliable to answer a question) they actually put Mr. Bruce Brisson on the phone for me; I was impressed. MIT probably mistakenly thought that the defective connector caused your damaged equipment & absorbed liability as a courtesy issue - so I am even more impressed with them now then ever.
Those 'famous boxes' contain passive group-delay equalizers which control time alignment of various fequency ranges, such that they all arrive at the load end of the cable in-phase. While these components are a serious issue of debate between various detractors & proponents of the technology, I must confess that although I too laughed at the idea for years, I stopped laughing when I finally decided to try their cables for myself. What happened? I bought some more!