At 275W max current draw, your Mc5300 should do fine with the P3! My Emo draws 300W, thus I’ve also ordered a P3 for “my modest” setup (driving Sierra2-EX Monitors)! The P3 is actually rated for 500W Short Term and 900W Peak Power, so don’t believe it’ll even break a sweat!!
FWIW, with my systems 1050 watts Max Component Draw Ratings (CDplayer-30w, preamp-70w, power amp-300w, powered sub=650w), in the real world playing music at my normal 80-85db listening levels, my new P3 is easily Regenerating Power to each component without ever hitting the Yellow (using 90%+ of the P3’s 300W rating) or the Red (using 110%+ of the P3’s 300W rating) output LED, it stays Blue indicating the unit is handling the loads well!
I’ve even pushed my system with strong dynamic orchestral passages (35 db quiet passages to 105db+ dynamic peaks), more than I’d dare listen to without hearing protection. The Output LED remains BLUE while the P3 not only handles this sonic thrill, but I can barely feel that the unit is even warm to the touch!
I have a tremendous recording of George Crumb’s A Haunted Landscape, performed by Arthur Weisberg and the NY Philharmonic (New World Records #326-2). Its dynamic range is really pretty astonishing. I don’t know the SPLs in my room since I have no way to measure, but with the M700s driving Maggie .7s, with the volume control of the SGCD at about 45 or so in a 2000+ cubic foot room, I’ve never seen the P3 even think about budging off of that first LED (blue on my unit).
I’m using a P3 with all of my source components. I used to have my McIntosh MA252 plugged into it but I found that my system became much more dynamic sounding with the amp plugged directly into the wall.