My Yamaha clips at 3/4 volume

I have a Yamaha M-45 and Aragon 28K preamp driving a pair of A/D/S L810 speakers. The problem is that the amp clips at 3/4 volume and a couple of times the preamp turned off. Does it sound like there's an issue with the preamp or the amp. When the clipping or whatever it may be happens the speakers have virtually no detectable distortion which leads me to believe that isn't the problem.
Do I just need more power for the L810's to satisfy my need for volume?
Thanks for any responses