help connecting minidsp DDRC-24 to Rega Brio? tube amps?

can this be done with my Rega, or do I need an amp with a line out?
also, has anybody had success using one of these units with tube amps?
IF your source come with built-in volume control, you can connect it to the minidsp input, the output of the minidsp connect to one of the line level of the Rega Brio. Set a fix volume of Brio to 12 or one O'clock, then use the source volume control for volume level adjustment. ( Same as HT set up if the integrated amp dose not equipped with pass-through )

Source --> minidsp --> integrated amp
                       l ---> active subwoofer