Not a 3A Sig but I do have the 2CE Sig II powered by McIntosh monoblocks MC 601, 600 watts per amp and never experience any falling apart. I love my 2CE Sig II as they just get better and better as it aged.
Vandersteen
After hearing many good things about Vandersteen speakers I purchased a pair of 3a signatures. They sound beautiful with chamber music or small group jazz but quickly fall to pieces with symphonic works or rock. Have other people noted this deficiency with Vandersteens?