192 from usb/spdif to NOS dac to amp

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.

Matt, the difference between traditional converter and
sigma-delta is pretty much the same as the difference between
CD and SACD. Instead of creating many discrete voltage
levels, corresponding to input code, Sigma-Delta creates
bitstream of varying duty cycle that after filtering (taking
average) delivers voltage proportional to duty cycle. SACD
is exactly that but unfiltered yet. There are several
advantages of Sigma Delta the most important is moving
quantization noise to much higher frequencies outside of the
audioband. Quantization noise in normal people language
means simply "steps". Sigma Delta has only one
large step (being one-bit converter) but repeated at very
high frequency. Any residue of the steps has very high
inaudible frequency. For SACD it is 2.8MHz.

I have always understood that NOS dacs are less effected by jitter than upsampling dacs. Also my Audio Note transport has no jitter reduction at all. Audio Note does not feel that jitter is really a problem with there gear.
Alan

What does sigma delta mean?

MattZ - absolutely, jitter is much more important to reduce than increasing the sample-rate, particularly when using a NOS DAC because there is typically no digital filtering.

Upsampling helps the most when the DAC is a Sigma-Delta and uses digital filtering. upsampling tries to mitigate the effects of poor digital filters.

Steve N.
Empirical Audio

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?

I would think an USB/SPDIF converter would improve the sound coming from your DAC’s USB input regardless of sampling rate. Audirvana I believe is capable of doing the upsampling, and I understand that upsampling is best accomplished by the program rather than via a DAC chip (that may be debatable and may depend on chip). The limitation as to the level of upsampling to be deployed by Audirvana should be the limit of the DAC input.

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?

I have a Metrum Octave DAC, which is a NOS unit. While the Octaves are not guaranteed to work with 24/192 (I believe 1:100 do), I'm from the lucky few and it does work with 24/192.

I use an Audiophilleo that can work with 24/192 as well. So my 24/192 files are played natively at the server, sent to the Audiophilleo without up or down-converting, and fed into the Metrum. Works great.

so the key question is what Arh asked: can your Audio Note convert 24/192 digital input into an analog signal? If so, I believe you would be good to go.

USB converters usually dont convert the data. They just pass it through and reformat.

A good USB converter like the Off-Ramp 5 would give you better results at 44.1 however, by reducing jitter even more.

NOS DACs usually are based on older chips,which do not support rates above 44.1 and sometimes 96.

Steve N.
Empirical Audio

If your D/A converter operates straight from 192kHz than it might get even worse since converter's THD is higher at 192kHz than 96kHz. My Benchmark DAC1 upsamples to very high frequency but then down-converts to drive DAC at only 110kHz (in spite of D/A chip being 192kHz capable).

I believe the coax input of your Audio Note will only recognize 16/44 redbook. What is the resolution of these native flac files? My experience with upsampling is it really doesn't add any new information. It is just allowing you to use a different path to decode the signal and therefore might sound better. Your Flac files into the audio note usb will probably never sound as good as playing cds into the coax input. By the way I have an Audio Note cd2 transport and an Audio Note2.1B dac as well as a Metrum Hex
Alan