Thank you!!  I actually got the idea for the color scheme from the layout of this forum...   The way the blue "who's online" tiles look on the black background caught my eye.   Teal is Rustoleum, think it's called "lagoon".  I'm all about those satin finishes lol

Wow.  That teal/blue color is stunning, and I really like the two-toned front and back.

@Thursday Thanks, dude!  Wouldn't have been able to do it without your triple prosound board!   Debating whether or not to backlight it, I really like the way it looks right now.

@Bitjacker: Did pre-pot for the 1/4" jacks to get as close as line-level as possible.  Post-pot for the 3.5mm, which is just for a headphone jack.  Had to remove the stock audio PCB to accommodate the  PS/2 jack.

More pics:

[Edited for grammar]

Yeah you gotta go prepot if your gonna be playing it through any kind of mixer. kaoss mixers have a loud whine if i use any post pot prosound.

That is a gorgeous Game Boy!

Went with 1/4", turned out great.  Thanks for the tips! 

Interesting.  Thanks for the advice.  I managed to get XLR hooked up and working, but I didn't have anything with XLR-in on hand.  Using an XLR to 1/4" cable, I was able to test one cable at a time with an old 15watt guitar amp.  Sounded pretty good.  A friend who does sound mixing/recording suggested I use XLR over 1/4", because the mixerss he sees/uses these days are more likely to have XLR than 1/4".  He uses late format mixers though.  Might there be a way to remedy the signal issues?  I just wanted something sturdy and versatile haha

I wouldn't recommend doing XLR.  1/4" actually works best with most non-DJ mixers. The modern standard for small format mixers usually has XLR inputs as balanced mic inputs and 1/4" inputs as balanced/unbalanced line inputs. If you try to plus in to the XLR inputs on mixers, you're going to have signal level issues!

So basically, everything is grounded except for the Pin-1 which is carrying the audio signal?

Thanks kineticturtle.  I usually do pre-pot and add an external switch for the internal speaker when I use RCA, and control the volume with a mixer.  I think I'd do the same with two 2 1/4 inches.  But I think that as long as I'm planning on an external mod like this, I might as well try XLR.  Same type of cable, so the wiring should be the same.  Just because I don't really know of many mixers that I could use two 1/4 inches with.

Pre-pot or post is a matter of preference. One conductor to each "tip", shields grounded together.

Thanks!  I'll give that a shot.

You'd just have to connect both shields to ground, I think.

Might be a dumb question, but here goes:

Say I wanted to build a DMG with 2 TRS 1/4" outputs for balanced mono... I know (let's say, for the left channel) I need to solder to left, pre- or post-pot.  I believe I then connect the shield to ground?  So then, to what do I connect the other conductor in order to balance the signal?  Maybe I have this all wrong...  Thanks!