Just to make sure before i solder the 40pin connector...

[CyberFly]

I don't see where it flipped. Head still goes to a tip and rim still goes to a ring. Am I missing something?

No, you are not missing anything. The head goes to the tip and the rim to the ring. The only thing is that the head piezo polarity is flipped. The ceramic part goes to ground/sleeve and the copper part goes to the tip/head.

I was just wondering if that would change the way I should wire the jack. Judging by your reply it doesn't change the wiring. I just wanted to be sure of that before I solder all my jacks.

[dmitri]

I see now. If these are DIY pads you may try both polarities and see if there is any difference. It is preferable that the first half-wave going from a piezo to an input is positive but in reality it may have no effect since MegaDrum will act on a second half-wave (incurring a delay of about 0.5-1ms).