I wrote about my experience at this link:
https://fcracer.com/nad-m33-review/
An excerpt:
Prior to setting up the Dirac Live, there was no discernible difference in sound quality between the M33 and the 390DD. Both have that wonderful inky black silent background with absolutely no hiss at any volume levels. If you held a gun to my head and asked me to be foolishly subjective, I would say that the M33 sounds more fluid, like the notes start and stop more precisely which allows the music to sound smoother and more refined. It may just be mental BS from having spent money or it may be something that can be quantified.
I’ve subsequently written that the single biggest improvement in my home audio experience has come from Dirac Live. Based on my personal experimentation, I would say the room is the most important, the speakers next, room correction third. For amplification, I’d focus more on power, connectivity, features, build quality and looks, assuming it measures decently.
I should also mention that I’m 100% happy with the M33 over the years. It brings hours of joy listening to music and watching TV. It helped me get through the challenging lockdowns we had here in China during the pandemic. I like the M33 so much that I’ve preordered the C3050LE for my bedroom.