A modern composite top plate has been installed in an otherwise conventional acoustic guitar. The design principles were essentially those proposed for wood substitutes by Schelleng [J. Acoust. Soc. Am. 35, 326–338 (1963)]. A graphite-epoxy was selected for its very high stiffness-to-weight ratio and its ability to achieve the orthotropic symmetry of a spruce plate. Further control was provided by the use of a low-density core. Tests indicate this sandwich plate construction closely matches the areal density, principal bending stiffnesses, and damping of a finished spruce plate. Attachment of the plate to the body has posed some difficulties, but the results of this first attempt are promising. A demonstration of this instrument will be given. [Supported by the National Science Foundation. Assistance from C.M. and M.A. Hutchins and J.C. Schelleng. Materials supplied in part by Hercules Inc.]