building your own mic preamp and a/d converter

I just bought a creative nomad jukebox3 from ebay:

Bought it to do some field recording, sounds, concerts.

Ideally I'd like something like this:

I can't afford it though.

I was wondering if there are any do it yourself plans I can use to make my own mic preamp and a/d converter. I would like to have professional quality and it has to be portable. What parts are recommended? How difficult is this to build and how much would it cost?

I'd also like to have a meter for understanding the levels going out of/into a device so I can correctly set the input levels on the next stage, in my case, the NJB3 [which has input metering]. Any do it yourself plans for this?

Btw, I also own earthworks m30bx battery operated microphone:

which I intend to use for the recordings; I was wondering if anyone knows how to convert it into a directional boom mic? Any advice on how to do this?

Thanks, Marc