DDC Sound Improvements???

USB to your Gustard X30? or -(Maybe I am reading it wrong but it may have I2s output too?) If it does you can use that connection to your X30. I see it does have a clock out feature so down the road you can get a nice outboard OCXO clock instead of the DDC for added refinement. 

I2S may work fine with some components but, in general, is over-rated as a connection protocol between two audio components and is not likely to significantly change the overall sonic presentation of most DACs compared to an optimized S/PDIF or USB connection (IME). 

@fthompson251, I’ve been seeking and taking your advice for years on matters audio. Because of your and @mitch2’s posts, it made me look into and figure out exactly what an asynchronous USB connection is and more importantly what it does.

If one could figure out away to add a nice outboard OCXO clock instead of the DDC for added refinement. That right there got my attention.

Any OCXO clock recommendations? Anyone? Anybody a fan of LHY AUDIO?

Yes, I would look into the LHY models. Alvin should be helpful in leading you on that decision. I honestly don't know much about master clocks other than getting the best OCXO you can afford. Denafrips makes a couple master clocks too. 

I don’t why I didn’t think of looking at the GUSTARD brand? As you introduced me to that brand.

lhy makes good stuff, excellent quality of parts and assembly, alvin is very responsive and a nice guy to boot

paul pang (taiwan) and afterdark (in hong kong) also make excellent, cost effective standalone ocxo word clocks, with 50 or 75 ohm outputs

with my ether regen, adding a strong clock on the clean side unit made a substantial difference in sound quality, as much as i did not want to believe that would be the case before trying it

I'm using an Innuos Zen MKiii streamer with a Gustard U18 ddc and a Gustard X-30 dac.  I'm also using a LHY ock-2 clock which is connected to both the U18 and X-30.  I've tried both sine wave and square wave.  I prefer square wave in my system.  The LHY clock definitely made an improvement. 

I've connected the U18 to my dac via i2S and coax.  With a good coax cable (Black Cat Silverstar 75), I hear little difference between i2S and coax.  I couldn't say which one is better.

When I got my X-30, I reached out to both Gustard and Innuos to see if they thought that I should connect the streamer to the dac via USB and eliminate the DDC.  They both suggested that I continue to use the DDC. 

The U-18 works quite well.  I doubt that I would see much improvement, if any, by going to the U-26.  I've posed this question to Gustard and haven't gotten a response.