Abstract: The invention is an attachable string tension control device for adjusting individually and simultaneously the pitch of each and every string of a plurality of strings of a musical instrument, wherein said strings are pre-tensioned between two critical contact points. The attachable string tension control device is comprised of a base for supporting the following components: a roller assembly for receiving the strings, and an adjustable pulleys assembly for adjusting individually the height of each string, and a string holding assembly for preventing the lose of tension of the strings. At a position between the adjustable pulleys assembly and string holding assembly there is a shaft rotatably connected to the base for supporting a plurality of adjustable cams for applying tension to the strings when rotated, said shaft having a handle at one of its ends (NOT SHOWN). Each of the cams including a pulley for decreasing the friction between the strings and said cams.