Robot background noise

[AntKnee]

My robot build works, but is generating a lot of background noise when I am not playing, particularly in arpeggiator mode. You can hear it arpeggiating in the background when I am not playing.  In the octave and fuzz modes it just has a lot of fuzzy oscilation background noise. Can I add a cap or resistor somewhere to cut that off when I am not playing?

[AntKnee]

Bump for edits. (new problem)