192 from usb/spdif to NOS dac to amp

Good question. I was under the impression that the USB input was the only thing that governed any limit to 24/96. If data was routed through the coax the 24/96 limit was not imposed.

And Steve, should I be more concerned about jitter than resolution?

That's what I think too, so if Audirvana sees the converter as being capable of 24/192, it will process at 24/192. At that point, the output of the converter sends data to the NOS Audio Note dac.
The dac cannot over sample anything and it has no way of telling that the data has already been up sampled before it arrived via the coax.
If this is correct, the finding the right converter would be next. I am thinking that this is where jitter would be something I need to understand a lot better,
Steve, is my thinking aimed in the right direction?

What does sigma delta mean?

Just bought this usb/spdif converter. Hoping that I can learn a few things with it.

Product Description (taken from site)

U12 uses the XMOS professional audio field X-CORE 32BIT / 500MBPS digital signal processing unit, the inside has 8 cores, with powerful multi-core multi-thread processing capability, is being outstanding in industry and provided a USB Audio Class 2.0 digital audio solution. Product Features: • Use XMOS programs to support 32B 384khz asynchronous 2.0 (recommended ASIO output when using USB) • using an independent power supply. Built-in sealing ring cattle, multiple sets of multi-level regulation. About the importance of independent power, I believe we all know. • optimize the design of the audio clock circuit using 0.1PPM precision active crystal to provide a more perfect clock signal to digital audio. Provided for by the two crystals were 44.1 / 88.2 / 176.4 / 352.8Khz and 48/96/192 / 384Khz series rate signal only after the selected clock rate selected work, work another one audio clock stop, put an end to the mutual interference may bring work simultaneously when the two clocks. • A total of four kinds of output: Coaxial (RCA), optical fiber, AES / EBU, IIS (HDMI port) Coaxial fiber AES / EBU output formats IEC60958 and AES3-r2009 standard limits the maximum support 24Bit / 192kHz; IIS can transmit 32B 384K • smart switch, USB has a current interface to boot. Interface with the computer switch and switch machine (computer to be set off USB power failure), or unplug the USB cable directly to the shutdown.