streamer to DAC connection


streamer to DAC connection:  optical, USB or COAX best?
128x128jw944ts
for what it is worth to those on this tread, I am now aware there are some articles about this subject, but interestingly, neither my DAC or cable manufacturer recognize this as an issue.....I would certainly think they would if it was a significant issue, as it would cause consternation about their products and the resulting sound....
USB best.  No documentation to prove it.  Just lots of testing. And if you want to listen to DSD, which is to be recommended as it sounds better if a genuine DSD recording (ie not simply upsampled) then you need USB. 
OP. I'm with you on this one. Nothing wrong with a question to learn. Some people are extremely touchy and sensitive. The proof is in the pudding, and that is, how does it sound???  :-)))
I read this thread with some interest as I am upgrading my DAC and am interested in the question posed.  It sure seems to me the question was answered in a durect and helpful way, and the original poster is somewhat belaboring the point after receiving the answers, maybe not hearing what he wanted to hear.  We who use the internet and internet forums to get assistance for our own uses should have some basic research and searching skills to get more information to satisfy their curiosities.  Especially since we all know that there is a great deal of misinformation on the net, and who knows who has what stake in giving their answer.