So I'm getting a high-pitched hum in just the headphone output when I plug in my KeyStep via USB.
- I am using a choked USB cable from my Axoloti to my computer.
- I am using a non-choked USB cable from my Axoloti to my KeyStep.
- The noise goes away when I unplug my KeyStep.
- The noise gets louder when I swap the cables.
- The noise does not go away when I use a USB phone charger instead of my computer.
- The noise gets quieter when I make skin contact with the metal backplate of my KeyStep.
- The noise goes away when I apply pressure to the metal backplate (skin contact optional).
- The noise goes away when I flip the KeyStep upside-down.
- The noise sometimes goes away when I move my cables around (I can't find a pattern).
My KeyStep is modified to have an Axoloti (sans-midi/power) embedded inside it. I covered the metal parts up with a couple layers of scotch tape, so there shouldn't be any shorting or anything. The odd thing is, the noise is only present in the headphones out. I really hope this problem can be fixed, I'm using the line out to power a small phone speaker so the gain has to be as high as possible (not good for ears!).