SACD

I don't think it's possible to get the digital signal out from an SACD directly to that DAC. Some of their higher end old models used to have a thing called Denon Link which I believe used an Ethernet format to carry signal from their players to their matching processor. I had the set back in 2009 I want to say? Each component was around $7k at the time, sounded pretty great. 

You would need an external device to extract the signal, like the one linked above. There have been a few other models over the years but I can't remember the names. They aren't very common.

ghdprentice's chart is correct.  Unless you have an HDMI digital output in the Denon (and input in the DAC) you won't get the SACD layer to play through your DAC.  However, you can get the CD layer of the disc (as well as a CD) to play through the DAC.

If your SACD player has i2s or HDMI out, then you should be able to use the DAC,  If not, you're stuck with the internal DAC of the SACD player. 

For HDMI, you may need a HDMI to i2s converter, which can be had for less than $100 (I wouldn't waste my money on that GeerFab gizmo). 

If your external DAC is better than the one in the SACD player, consider a used Oppo or other universal player that will play SACDs and output via HDMI and use a HDMI to i2s converter.  I do this with my Oppo UPD-203 and send the signal to my Rockna DAC, which sees a DSD 64 signal.

I had a feeling that was the case that I wouldn’t be able to go through the external DAC.  Some kind of legal thing with Sony.  I have no issues , however, with the sound of the Denon 1700.  It sounds really nice as is.

@big_greg That GeerFab gizmo is tremendous read the Sterophile review of it.  This thing is so good that I am helping my friend set it up with his $26k DAC and another $12k DAC (which I just bought) to demo at shows (he sells DACs and others). Why, because it is better than streaming, especially at a show.

I believe they are the only people to natively get a DSD stream out of SACD. You are not stuck with the usually crap DAC inside an SACD player.