Originally, my 5v was just an Arduino wall wart wired into the whole thing with these:

https://www.mouser.com/ProductDetail/474-PRT-10811

Now I'm using the same barrel jacks, but with an old linksys wall wart.

That said, it's not an ideal situation, and I'll most likely build something like this in the not too distant future:

http://musicfromouterspace.com/analogsynth_new/WALLWARTSUPPL...