Weird science!
Ok, I was concerned about the 520's break in progress until I made an accidental discovery. It seems they were out of phase!
Before I got them, I was listening to Klipsch Reference speakers through a preamp and LM3886 amp. When I got a dac from HK , I had to reverse speaker polarity due to the dac (I presume). This was verified with my Stereophile test cd.
When I got the 520's I hooked them up the same as the Klippers then later connected used my DIA in lieu of the LM3886 amp. About three days ago, I tried out the test cd and, low and behold, they were out of phase! What was correct for the Klippers was not right for the 520's!
Now, I wonder if the phase shift is due to a difference of x-overs or by deleting the preamp and LM3886 and replacing it with single passive amp?
Any ideas?