Warm relaxed digital coax

A stock Forte 4 and AR i50 is not resolving enough to easily reveal differences in digital coaxes.

But, you could try an Ansuz cable, which could sound a bit more detailed (after pulling teeth) and maybe offer a slightly different tonal balance in a more resolving rig+room. A GR research upgrade for your Forte could make it more resolving, if you’re a diy kinda guy..

Thanks guys for the feedback. Maybe i

will try a Cardas or Kubala. 

DH Labs has been my go to the past 3 or 4 times I've ordered cables.   Excellent quality for the $$$     

They usually have a sale on one or two product categories each month.   I bought a pair of Air Matrix Cryo at 20 or 25% off.  I also have the D-750 coax digital and the Mirage USB when they were on sale too.  All excellent quality 

I am going to order their Prelude speaker cables for my Forte IV soon.    

Snake River Audio is supposed to be warm and well made.

Is there a reason why you can’t use USB with the dac?

Because if you can, there’s a really nice Audience AU24SE+ USB cable on USAM right now. 
https://www.usaudiomart.com/details/650117580-audience-au24-se-dual-wire-usb-one-meter/