Abstract: There is disclosed a new and improved device which facilitates the tuning of musical instruments to a standard frequency with speed and accuracy. The device includes an indicating means comprising a plurality of light emitting diodes. The cathode of each diode is coupled to a saturated audio amplifier which is adapted to be coupled either directly to or by a microphone to a musical instrument to be tuned. The anodes of the diodes are coupled to an oscilator which provides any one of a plurality of selectable output frequencies which are harmonically related to a corresponding plurality of standard frequencies. The number of diodes, and the relation between the harmonic oscilator output frequency to the standard frequencies are such that when the instrument is in tune, one half of the diodes appear to be continuously and simultaneously lit.