Do I have to get a CD player to sample DSD on my digital rig?

No.

And furthermore it is illegal to copy music from "a friend." Unless you get creative at breakin’ the law (no tips coming from here) you’ll have to buy some tracks for yourself.

Was there any mention in the previous threads about copying tracks?  The OP expressed a curiosity to hear DSD but nowhere stated he intended to rip anyone off.

  Which segues to another point about DSD, which is that the software (SACD) or the downloads are premium priced.  The downloads also are big files so make sure that you have a lot of storage.

  I have some DSD downloads but most of my DSD is on SACD, which I output from my Oppo 105 into the HDMI input of my Bryston DAC.  Some of the recordings are truly outstanding, close-eyes-and-musicians-in-the- room experience.  However a poorly recorded file won’t be rescued by DSD.  

Just a note - you can use the Oppo BDP-105 (as well as other Blu-ray disc players) to rip SACDs if you want to archive them. I’ve done this myself with all my discs.

There are details here - https://hifihaven.org/index.php?threads/rip-sacd-with-a-blu-ray-player.3652/

@jwpstayman 

Easy to misunderstand my comment, it does play the DSD layer, not the SACD

tweak1

... it does play the DSD layer, not the SACD ...

The SACD layer is the DSD layer.