So I called Max at Apogee to confirm what I already thought. The c777 clock found in the Big Ben and DA-16x are not similar, they are exactly the same. So you should not be hearing any differences. I am not sure why you are; you may want to double check how you are doing this shootout to make sure the differences aren't caused by something else.
Interesting. When I sut up our rigs with Max, I had this discussion and in keeping with everyone knowlege, they are exactly the same. I will try to re-amp something and record to one unit clocked internal and one via BB and see what comes out. I'm sure I will hear no difference, but as with everything else, I'll have to listen to give my 0000 0010 cents