More info at www.sweetwater.com/store/detail/KP500SN/. The Motion Sound KP-500SN stereo keyboard combo amplifier lets you take advantage of the dimensional, lush sound field made possible by many modern keyboards. Though it’s very lightweight and compact, the KP-500SN gives you an amazingly big sound that’s great on any stage! An onboard proprietary 3D expander control expands the stereo image into a fantastic 3D sound that you just have to hear to believe. At 250 watts per channel, this amp has plenty of power, and an array of inputs and outputs make the KP-500SN great for any setup.