Welcome to SDS Labs, we have been rebuilding the Quad Electrostatic Loudspeakers (Quad ESL) for over twenty years. These loudspeakers are in many ways still state-of-the-art even more than 45 years later. We rebuild the original ESL's as well as the ESL-63's and newer Quads (988, 989, 2805, 2905, etc) to original performance or better. SDS Labs provides component rebuilds including power supplies and panels, as well as complete rebuilds of the speakers. Our rebuilds restore aging or damaged panels to factory performance, repair and rebuild power supplies and input electronics. Our aim is to restore your quads to original condition both sonically and visually. We also provide information on how to rebuild quads yourself for the ambitious.