series and illustrated by the reference symbol le 1 are mounted as a light emitting device and this is the same as the circuit configuration illustrated in fig2 that is cathodes of current regulator diodes cr 1 and cr 2 with anodes being respectively connected to the terminal pins pin 2 and pin 3 of the output connector are commonly connected and the leds are connected in series to a common connection point of the cathodes so that a drive current is supplied from the phantom power supply to the leds through the common connection point further a cathode of the leds connected in series and illustrated by the reference symbol le 1 is connected to the terminal pin pin 1 of the output connector and the terminal pin pin 1 is used for light on off control of the leds then the audio output circuit illustrated in fig2 is ground connected with the microphone amplifier side using a frame ground terminal si of the output connector in addition a switch sw is connected to between the terminal pin pin 1 and the frame ground terminal si of the output connector and light on off operations of the leds connected in series and illustrated by the reference symbol le 1 can be remotely operated with the switch sw note that a zener diode zd 2 connected in parallel to the leds and a zener diode zd 3 connected.