I heard this speaker with MAC integrated which is 75w/ch. Sounded nice but was not able to play them at realistic levels. MAC would give up. Heard them in another store with MAC 100/ch solid state amp, it gave up playing Metallica at a relatively good level, but I would not call it too loud, or in that matter, it was not near reproducing James Hetfield in the room. Actually a right channel on that amp completely shut off. At another place I heard these speakers with C-J CT6 tube preamp and Premier-140 tube amp and it was really good, but we never went too loud. I liked it a lot with the C-J stuff. Smooth and strong at normal volume.
Personally, having owned the N803 for number of years, I had them set up at various times with McCormack DNA-0.5 Deluxe, then DNA-125 and now DNA-225, which is a really nice match. The more power the better for these speakers. B&Ws are power hungry. Keep that in mind. They will sure play with that Pathos amp, but I doubt 70w/ch would make the speakers or you happy. I would go for a tube pre and solid state amp. BAT tube pre and solid state amp would most likely be a very good match for these speakers. Or that C-J combo I mentioned above. Good luck.
Personally, having owned the N803 for number of years, I had them set up at various times with McCormack DNA-0.5 Deluxe, then DNA-125 and now DNA-225, which is a really nice match. The more power the better for these speakers. B&Ws are power hungry. Keep that in mind. They will sure play with that Pathos amp, but I doubt 70w/ch would make the speakers or you happy. I would go for a tube pre and solid state amp. BAT tube pre and solid state amp would most likely be a very good match for these speakers. Or that C-J combo I mentioned above. Good luck.