MK 103 alternate LEDs

I was hoping to substitute the red LEDs for other colors. The forward voltage varies by color and seems to impact the sensitivity of the microphone. Can you suggest a way that I might use different color LEDs?
Green 3.4V
Violet 4V
Blue 3.2V
Pink 4.5V
Yellow 2.1V


Think I figured it out but can you confirm. Need to either swap out resister R9 for lower ohm based on formula or reduce the number of LEDs connected in series

Formula (9v-LEDv x number of LED)/.005= resistor in ohms right?

Is there more to it?

(9V-(led voltage x number of leds))/0.005 is more correct :slight_smile: