What kind of tubes are in the MC275, and how old are they? I found that 6550 type tubes were not that great at reproducing snare drum when I used them in my Jadis amps, though perhaps not to the extent you're describing. I would not suspect the speakers at this point.
Bolero:why can't my system reproduce snare well?
For those of you who don't follow my posts religiously, I recently purchased a pair of Martin Logan SL3's. I love them; they especially excel with voices. However, last night, I was listening to Bolero, and the snare sounded terrible. It sounded muffled and faint. I adjusted the settings, and nothing helped. I am using a MC275 and c2300, so I assume the problem is with the speakers. Any suggestions, ideas? Thank you in advance.