getting rid of interference noise of the daisy seed?

hi friends,

I have problems with my daisy builds, they produce a lot of interference noises. A bit of a hum and a bit of a beep. I am running sparkfun rgb encoders and an oled display, using the 470uf cap directly at the oled power lines (otherwise it would be much worse). What else could I try? I can hear the interference change frequency depending on how full the screen is.

thanks!