An adapter for mounting an instrument or accessory device to microphone stand head includes a conical body having an overall length with a maximum outside diameter and a minimum outside diameter, an elongate mounting post having an overall length, the mounting post contiguously formed to or otherwise fixed to the conical body, the mounting post and conical body aligned to share the same longitudinal center, the mounting post bearing external threading from the free end of the mounting post down the post to some length, and an end cap having a uniform outside diameter and an annular threaded mounting seat provided at proximal center of the threaded end cap, where the mounting seat threads mate with the external threads on the mounting post.