Finding a knob "may" be a problem. There are two or three ways to solve the pot issue.

This knob controls two separate functions, VOL and Effect.

So I read what you said again and I assume the knob is split and the outside part holds the inside part on.

Billy


“Amazing! I’ll be working with Jaco Pastorius, Charlie Parker, Art Tatum, and Buddy Rich, and you’re telling me it’s not that great of a gig?
“Well…” Saint Peter, hesitated, “God’s got this girlfriend who thinks she can sing…”