Just installed a bluesound node 2i , quality not so good

Yes it does! 

in reading responses that you need to run this through an external dac what is the purpose. I run MacBook Pro usb to external dac into preamp. Already had the Mac so I was able to put all of the money into the dac. Why do people continue to over think streaming.

You don't "need to run this through an external dac".  If you want it to sound better, then you can.  If you're happy with the sound, then don't.

I was held hostage by a group of audio terrorists,and they forced me to use a DAC. It wasn’t like I had a choice! 

    Seriously, for me,I ran node products for a couple of years through the analog outs. I was pleased with the sound. I just wanted to see if I get better sound. Just like any other facet of this hobby. 

+1rocray!
I  was wondering who was holding the gun to whose head to "make" them use a DAC.
Op asked and was given opinions, nothing more.