First question. Does the receiver have preamp outputs?
That's the only way to add an external power amp into the system.
Also, I'm not knocking Bose, but their 901 series require an equalizer be inserted in the signal path at line-level to sound the way they were designed. How did you manage that?
FWIW, the good news is that the Mac C24 is a fine.preamp.
The bad news is that it's only a preamp. You'll also need a power amp to drive any speakers.
The good news is that you could easily insert that equalizer between the preamp and whatever power amp you purchase.