Help! Speaker picking up noise from Arduino serial clock?

I am trying to build an Arduino based lightsaber and for that purpose I have connected a Adafruit Mono 2.5W Class D Audio Amplifier with a small 4 Ohm 3 Watt speaker and a micro SD card module where the sound effects are stored. Everything works fine but I have an unwanted ticking sound in the audio that seems to come from Arduinos serial clock. The microSD modules clock is connected to pin 13 and I can see the LED pulsing at the same interval as I get the ticking sound. I also get the sound when I upload a sketch and the LED flashes. Does someone know how to remedy this problem?

I am using the schematics and code AlexGyvers lightsaber:

Its normal to use a linear separate regulator for the audio components otherwise its pretty much inevitable you’ll
get digital noise on the audio. One thing to try is adding lots (2200µF or more) of extra supply decoupling.

Can you provide the actual schematic you are using, that site has several.