The MP200 bass amp provides 200W of all tube power through a quartet of 6550 or KT88 tubes. The output transformer has been specifically designed with Mercury Magnetics to provide a low end that extends past the audible range. You may not be able to hear it but I guarantee that you will feel it! The tone stack consists of treble, mid, bass and a focus control. The focus control shifts the midrange sweep of the entire stack allowing you to dial in just the right amount of cut. All of this in a 42 pound 24x9.5x9 package.