Cambridge Audio 851W: $420.69 in very good condition. Was my daily driver until I side-graded to two smaller mono amps. Been sitting under my coffee table since i went to dual mono amps but this thing is an absolute monster. 400w, truly balanced, toroidal transformer, can be dual monoized if you're running giant electrostats or something. I just dont need this type of power. dont have original box but i'll ship carefully. It weighs about 40 pounds so im eating a bunch of shipping.