Crunch Box high frequency noise with the gain pot

[oomnelson]

Hello !,

A friend of mine purchase an MI Audio Crunch Box, and the gain pot produce a high frequency "peeeeeee" noise when is beyond the middle of his way.
I suspect this is caused by the "in" conductor inside the box, because it doesn´t have an isolated wired.
I don´t modified this yet, because I want to be sure before to do it. Moreover, I think it´s a very basic fault by MI Audio, so I suspect about my diagnostic...
I hope someone can help me, and thank you for your time to read this post !