SACDs, DSD files, is upsampler necessary

I have had a Vivaldi stack for a few years and have used cds and 16 bit files exclusively. The files delivered from an aurender W20 via asynchronous usb into the upsampler.
I have recently been blown away by SACD discs (Dylan) played via transport to DAC excluding the upsampler. My understanding is that the transport to DAC pathway does not involve DOP, and if upsampler path is included (and DSD is allowed to pass through) the processing path through the DAC remains unchanged I.e no DOP. Is this also the case for a DSD file from the Aurender whether going to upsampler or DAC direct via asynchronous USB. Or is a DSD file always subjected to DOP whether direct to the DAC or upsampler. In other words is the upsampler useful if pure only pure DSD play back is required.
Perhaps I am a tad confused. Can some someone put me straight?

Hi Mark and welcome to the community.

I think that first and biggest item arising from your post is what is DoP?

You seem to be under a misapprehension that that DoP is something different from DSD and that the DSD data is turned into something else. DoP is DSD - it is the same data. The only difference is it is packed in a way so that it can be transmitted via an interface more commonly used for other forms of data e.g PCM. Please see this FAQ:

DSD pass through is really meant for when a sequence of mixed format tracks are received by Upsampler e.g. 44.1, 48,DSD,44.1. If the upsampler output is set to say 176.4 then the output with pass through set would be 176.4, 176.4,DSD, 176.4.

However Upsampler is only able to accept DSD input as DoP format on any input aside from Network which will accept the usual DSD .dsf and .dff formats. Unfortunately your Aurender does not have a network output.

In regard to your question:

If you only play SACDs from a dCS transport then the Upsampler is not required. However if you were to play DSD files from NAS then you would, of course, need to use the network player facilities of the Upsampler and this would involved DoP except with network connection.

However, in any case, the best interface with current dCS products is not USB ( irrespective of the data format it carries ) but network connection. Unfortunately the Aurender does not, I believe, have provision for this.

Thank you Pete for a very prompt reply. So the situation regarding the sacd is clear. So am I correct in thinking that a DSD file that leaves the aurender via the usb and goes into the directly Dac is managed as DOP as it would be going into the upsampler.
Many thanks

The file sent to the dCS component by USB has to be in DoP format in the first place. It is not turned into DoP by the Upsampler or DAC. I do not know how that can be done if your files are stored on your Aurender unless your W20 can output DoP.

I used to have a USB PC based replay system using JRiver MC. JRiver had ( has?) an option to output .dsf or .dff files as DoP and you need an equivalent of that.

Thank you once again Pete. You have hit the nail on the head and it now makes sense. The aurender does send DSD by DoP but only via USB and not it’s AES outputs. When I try to do so via the AES the aurender posts an error message in the settings.
Thank you and HNY.