To DDC or not to DDC. That is the question.

"I have been very impressed with the Merason house sound signature and suspect it has much to do with their purposely optimized implementation of the Burr Brown PCM1794 DAC chips..."

@mitch2 Yes, this and its discrete class A output section in particular, which plays a large role in the overall sound character of any DAC. 

As for what the OP might do, I suspect even a low to mid-tier DDC with SPDIF output might yield an audible improvement depending upon source noise performance (we don’t know what the source is), but I would upgrade this DAC before throwing a lot of money at it. 

@maprik Don't get hung up on USB. If we are correct about your USB card, it's not what you think it is and nothing remarkable. Try the Hermes. 

"Yes, this and its discrete class A output section in particular, which plays a large role in the overall sound character of any DAC." 

@ted_b - Absolutely. I suspect the output section in the Merason is another reason it sounds so good.  I never understood higher end gear that use op-amps in the output. The fact that the Merason is upgradable (to MkII and also to DAC 2) is another value-added feature.

@maprik I used this little gadget when I was streaming from mac mini and I recall audible improvement. Very cost effective and unlike to hurt anything. 
https://wyred4sound.com/products/recovery

worth a try before you commit to a larger purchase. And will most likely be useful even with the ddc. 

Hmmm interesting little tweak! Thank you! 

My only reservation is that the Hermes has no USB out and the USB input is the strength of the Merason. 

You could get a DDC to go in between the Hermes and the DAC (?) 

I asked AI and it said it was a good idea.