god damn it. next time read the childish scribbles known as my schematic correctly. (meaning use ESP because I didn't put that in the schematic)

Will do, sir!

Thank you!  This has been one of my more enjoyable projects as of late, and I am extremely glad that a number of people found them useful and of professional quality.

The reason isn't because I'm poor at soldering or do a sloppy job. I'm usually nice and clean with my work. The reason is that this is a GREATLY made product. It's extremely tight in there and hard to get into to, and I must admit that I kind of feel bad for making an aesthetic mess out of what was honestly a beautifully well-done product. Great job.

easy fix, although those wires are stiffer than nails

funny you didnt test for it, as for me, that was the first feature i wanted to use (×̯×)

So far I'm using only MIDI in, but in the near future I'll suck out the solder from the midi-out din and resolder it. Thanks for warning us.

The one on the left depicts the way they were wired.  The one on the right shows how they should be wired.  Just switch the red and green wires on the MIDI out socket and everything will work just fine.  Don't switch the wires at the board, as this will mess with the color coordination (red=positive voltage, black=ground, green=data), but more importantly, unless you have a dedicated desoldering tool, you will not be able to get the wires back into the holes after you remove them.

PERFECT.

i'll do this tonight and report back. thank you.

no offense, but didn't you test your units before you shipped them?

I did, I just didn't test that particular feature.  I didn't know how to at the time.  Turns out it is as simple as connecting the MIDI in and out on my computer simultaneously to the ArduinoBoy to make sure the same MIDI data comes back.  All future units will be tested in this manner.

Sure thing.  First thing after work tomorrow.