Ok. I like the way you phrase it as headroom instead of gain. That is what I was hoping to achieve, though, ultimately. To maybe experiment with the way it stacks with other pedals. I only thought of adding an 18v as a way of having "all the options" , as it were, and by moving the trimmer to a pot on the face of the enclosure, I'd be able to create interesting tones. I mean, I have the board, so I figured why not? If you think it's a waste of time, though, I won't experiment to try. I'll just build it easy.
and as far as "bought or built the wrong pedal", I'm not sure what that means. I might have, but that's why I'm trying to understand what it does when you run at 18v or at least make sure I'm doing it right if I do decide to experiment. I thought we were all kinda into modding and figuring out how stuff works?
My problem is I literally know very little and am looking to others for help when I need to understand stuff. I'm assuming you've already experimented with this, by the way you say it's unnecessary, so I can only go with your recommendation.
My only real question, still, is about wheather the polarity protection is on the main PCB or if it's ommited and replaced by the components on the 9v/18v PCB and I believe TGP39 may have answered this for me.
So thanks everyone, for your patience!