Hmm.. it doesn't work with the Windows version of HQPlayer either. It refuses to play them. And the same as in Linux: DSD512 is maximum. I would like to know how did you play these DSD1024 files from nativeDSD with the Pro iDSD. Which OS and which player? Did you test/play them at all, natively?
OK, here's how it goes:
USB audio as currently defined is limited at a maximum of 768kHz/32Bit/2-Ch or DSD at an equivalent data rate (DSD512/2-CH).
Recording systems for DSD at this point max out at DSD256 (Merging Pyramix).
DSD512 is mainly used for software up-sampled PCM by some enthusiasts.
If set to no upsampling & Bitperfect(+), our iDSD Pro applies no digital processing and works for PCM as "bitperfect/non-oversampling/zero-oversampling/NOS/etc" DAC up to 768kHz/32Bit and for DSD as direct conversion system (no digital processing) up to DSD512.
As some customers desire upsampling to high sample rates and the sound of certain digital filters (e.g. the 16k very long symmetrical FIR "Transient Aligned" filter) we provide a FPGA based flexible upsampling engine, which can handle both DSD and PCM input to either 16X PCM or DSD512/1024 and DSD up to DSD256 to DSD512/1024.
DSD512 is always left untouched (namely native) as it is already upsampled and multiple upsampling processes in series are not recommended.
In effect the iDSD Pro can function across the whole gamut of DAC technologies, from non-oversampled PCM and direct DSD conversion to highly oversampled PCM or DS(D) systems with multiple digital filters.
It leaves the choice of what sounds best to the customer, instead of imposing some perceived ideal (whatever that Ideal may be) without alternative choices. This parallels the choice between solid state, tube & tube+ operation for the Analogue stages.
TL;DR: Pro iDSD does native DSD playback up to DSD512 (internally upsampled by this machine to DSD1024), as there are no native recordings above DSD256 and USB as is doesn't go above DSD512.
