USB connection to DAC: multi stage improvement

@mitch2 +1 

“It seems clearly there is no one-size fits all approach.”

Congrats to the OP for their persistence/diligence in pursuing their sonic goals. 

I do want to comment briefly that the approach taken by Berkeley Audio ‘Designs (convert USB to SPDIF) was developed quite a few years ago. There is no question of the superb performance of their DACs. However, USB interfaces have advanced markedly in that time. So has the availability of hi-res content. Those factors make USB more attractive to me and many manufacturers. While it used to be orthodoxy to prefer SPDIF or AES EBU, that is no longer the case.

In my own use case, I’ve recently acquired a new streamer in one of my systems (Synergistic Research Quark) which can be used as a roon core or to output digitally. I compared the stream via Ethernet to the renderer built into my DAC (works great) vs its output via USB into my DAC (even better). FYI: The only digital output offered by the Quark is USB. (Same for the JCAT S1 Evo under consideration for one of my systems). 

A relevant tangent:  surprising to me, I am now happily using Roon for library and streaming management with the Quark. Some may recall I’ve been critical of Roon in the past for its sonic penalty. 

Things change, technology advances and the complexities of making the nearly unlimited variables in our respective gear work seamlessly (it often doesn’t) mean that an approach that works well for one may not work well for another. Absolutes I once held are now easily disputed by my own experiences.

Plenty of great comments in this thread, shows how good this forum can be. 

(that's a thumbs up, not a hand shake icon)

I will confess, all this digital stuff makes my head spin. I have no interest in even attempting to understand how/why because it would take decades, and then I'll not even know 5% of what some of the experts already do. I will trust some of them instead. (the two mentioned below are on my list) 

@mitch2 

Interestingly, Aries Cerat has just released a $12K interface (Hronos-Project X) (link) that accepts a USB signal and feeds their DACs a customized discrete signal on a board that replaces the USB input board.  They imply it makes the source/streamer quality mostly irrevalant and that it achieves a level of sonic improvement that is comparible to upgrading to the next higher DAC in their line-up.

Not sure if there is any optical isolation in Stavros' solution, but sounds alot like what Andreas Koch has done with his MPS-X or USB-X4 isolators. 

USB-X4 Purpose:

this simple USB to PLINK interface is designed to isolate any USB source from the sensitive DAC via our high quality, synchronous fiber optic PLINK connection. It borrows this concept from it's bigger brother, the MPS-X, which is not just limited to the USB interface like the USB-X4, but also includes a variety of other interfaces and features as well (see MPS-X product page for more details). Any digital source with a USB host interface can connect to the USB-X4 which then is connected to any of our DACs(*1) through PLINK. All asynchronous clocks that are mandated by the USB interface standard and any other digital noise from the source are therefore kept from entering the DAC where they would always cause some audible deterioration. Asynchronous data streams from the USB source are carefully filtered with our PDFAS algorithm and synchronized to an internal high quality audio clock. This results in a dramatic sonic improvement when compared to a direct USB connection to the DAC. The sound stage becomes even more defined, the performance even more liquid and overall more "analog-like". A valuable addition to any of our products

@mclinnguy if you haven’t already, try asking AI about the whys and wherefore of digital audio.  Depending on your questions I think you’ll be amazed at the answers.  I know I was.

@marco1 

Are we sure what pops up is accurate? Check out this link from a few weeks ago, it is comical how wrong AI can be, and yet how "confident" it suggests its answer is: 

https://antipodes.support/t/antiopdes-k41-and-k22-mola-mola-tambaqui-volume/4449

@mclinnguy yep you have to be careful. As their disclaimer always reminds you, AI can make mistakes too.  I have found more often that not though that they are usually right on with their advice. I particularly like when they give you the mechanical and electrical engineering explanations of what you to can expect to hear and why you hear it.