Nice! Yeh, I read the “Macchiato Quick Start Guide and Reference Manual”, so I went out and got a 9V center-neg wall wart. I was pleasantly surprised when that fixed the issue. I have a garbage battery in there now — good to know that a better one might help. The ground plane thing sounds pretty cool.
I s’pose I could try to whip up a case if pressed — I have some OpenSCAD experience. I hope one of these days comes soon though. Remembering which of that row of 9 potentiometers does what is pretty daunting. A laser-cut case might be interesting too.