Been wanting to build this for a while as it does sound good. However, a couple of things about the article leave me scratching my head.
You can see the second IC is used from the photo, although the article claims it's unnecessary. Fair enough. But five 9v batteries wired in series for the phantom power, and four batteries for the +/- 18v is A LOT of batteries! There's got to be a better way to provide the necessary power for both?
(and I'd say phantom power is essential on a preamp... Looks like its missing from that layout).
Yeah, he just shares the entire schematic and then just describes what he left out or changed.
You can also power with a power supply, but you definetely need to use some filtering caps.
Not very involved when it comes to xlr signal and phantom power, but from what I've gathered it isn't so difficult to "harvest" the power. Just do some research and you can find out how.
Also, if you are planning to use that circuit for any kind of recording or serious use, I would advise against it :)