Hi Alan,

If you have some time to review my questions that will be appreciated.

I did some tests:
1. CD-preamp-amp main in: drive one channel and two. not much difference
2. CD-preamp-amp line in: getting better, more control. one channel or two, not much difference.
3. CD-amp line in: even better. can go higher volume without feeling strained.

Questions:
1. So NAD amp can handle the incoming sound well with its preamp than Oppo, correct? Would NAD soft clipping feature distort the sound so I shouldn't enable it?
2. If M22+EPC500 is a good combination without huge investment on high end floorstanding speakers, then next step should be upgrading the AMP. What would be the recommendation? An AMP with sub pre-out and high power (>175W)?