EWS88 MT + Mic + Digitube + s/pdif

[Rxman]

Hello

What I have:

I am currently running a Terratec EWS88 MT with a stereo receiver, cassette deck and external CD player.
This system does everything I want, but now I am ready to
add a microphone.

What I want to do:

Record primarily vocals (speaking), and possibly some music
(flute/woodwinds - my Daughter).

Questions:

From what info. I have gathered; using a PreSonus Digitube and
the Terratec, I should be able to go s/pdif "out" from the Digitube
to s/pdif "in" on the Terratec. Is this all there is to it?

If this works, what type of microphone ($150 range), would give good results?

Thanks

Rxman