how do i get my mac minito recognize my usb-spdif

bought from a friend a jkenny modded M2tech converter. hooked it up to my 2009 mini after installing audirvana but neither os10 nor audirvana recognizes the converter as an audio output device. only can choose internal speaker in the output setting. do i need to load special drivers? my dac locks onto the converter just fine but the mini doesnt. any help appreciated
Open audio midi control panel under utilities and see if it is recognized there. Is the dac recognized?
If it is a first-generation M2Tech, you will need the correct driver loaded. jkenny can point you to this.

Steve N.
Empirical Audio
Yes, there was a driver missing and jkenny has send me a download link. All works fine now. thanks!