Thank you for this quick reply and great musical taste by the way.
I have investigated many options before buying the Quad 3 and the Revela 1. As I have ripped all my CD’s in Flac/DSD I found in Audirvana Origin a trustworthy musical companion, after years of using its legacy 3.5 player.
I have been a Quad lover since I bought my first proper system to actively listen quality music on LP and later CD. I still have my 1980 set of Quad 44/405, that will be serviced in the next couple of months. Although they are seem old, they still have a –to me anyway– likable warmer sound that goes well with my predominately classical music collection.Over several years, I have curated my collection based on both musical performance and recording excellence. Tip: There are plenty magnificent musical recordings to elevate your soul albeit not the best recording. Musical performance is and has always been my primary focus. Being involved in this process is a very joyful occupation in itself as well.
Returning to your question: it all depends! If your PC is very near to your D9 (< 1,5 m of one-length audio grade cable) than using a direct USB connection will provide you maxed out possibilities of using the top-tier DAC in your D9. The Audirvana Remote app will be the everyday controller of selecting music in Audirvana on your PC. My initial direct USB test on my Quad was very favorable (32/384 PCM and DSD 512) compared to the relatively ‘limited’ 24/192 using coaxial cables. To be fair, this second best option sounds already out of this world, given a suitable hi-res recording. If your PC is near your D9 and you have the right cable available (or are able to lend it through your friendly dealer?), I would opt for direct connection right away. This will make the best use of your initial investments.
The reason I chose the WiiM Ultra was threefold. Firstly, I wanted a stable streaming platform with a future proof update system, Secondly, I wanted to incorporate a subtlety controlled subwoofer to supplement my Revela 1 (which is actually not in use right now because the Revela 1 have for now excellent bass response in my living/listening room. Maybe applicable for my ultimate fine tuning in the future!?!). Thirdly, Wiim has an option to improve the frequency response in your room and to synchronize the subwoofer output.
It all is going te be an interesting project. When my USB cable arrives, I will initially connect my Quad 3 with my MacBook Air. Then I can experiment with the expansive options Audirvana provides in streaming direct to the integrated DAC inside my Quad 3. Eventually, I will install a Mac mini as control unit running Audirvana and hub for my wired NAS.
I would postpone the purchase of the Zen in preference of the direct USB connection with your PC running Audirvana. On the basis of these results you can –if necessary– evaluate further actions. Mind you, you have a top-tier DAC in your D9 that will be underutilized by adding a streamer for no advantageous musical reasons.
Answering your last question: it will max-out at 24/192 using a coaxial cable and at 24/96 using an optical cable. USB is the best option into the future to obtain maximal use of Audirvana and the DAC in your D9.
If you have any questions, please let me know. I like to learn from your experiences in improving your musical enjoyment and beyond… as well.
Have a nice weekend and hear you….
PS: Could you tell me what you have connected to your D9 and the reasoning behind the current setting and what your ultimate goals are?