Dave,
I do have the Mad Scientists discs, but I think the Sonic Tonic is better. I did find that too many of them will squelch the dynamics. But one on the end of the IEC should not dull the sound.
Anyway, next place I plan on trying the Sonic Tonics is inside my breaker box next to the incoming power lines and on each of my 3 dedicated circuit breakers.
ozzy