Phantom DAC Chip Upgradeable?

[fritzcurtis1]

In reading the white paper on Devialet's website, it states that the Phantom has the Texas Instrument PCM1798 DAC in it.  I did some digging on the Texas Instruments site for this chip and found out that it does have DSD capabilities available.  I wonder if this might be a future upgrade down the line.  Might have to be direct wired for this to happen as I'm not so sure of Dialog.

[ogs]

That is more or less the same as Expert amps (using PCM1792). DSD will have to be converted to PCM inside the unit before passing through DSP and volume control. So a DA chip with support for DSD is not too helpful as DSD can not be run through signal processing, only PCM can. A firmware update enabled DSD support in Expert amps. Might be possible for Phantom too, but then the conversion to PCM could also take place in Dialog.

[jonstatt]

That is more or less the same as Expert amps (using PCM1792). DSD will have to be converted to PCM inside the unit before passing through DSP and volume control. So a DA chip with support for DSD is not too helpful as DSD can not be run through signal processing, only PCM can. A firmware update enabled DSD support in Expert amps. Might be possible for Phantom too, but then the conversion to PCM could also take place in Dialog.

There is a hybrid format called DoP (DSD over PCM) which avoids having to truly convert DSD to PCM but uses a PCM container to work around some system limitations in an attempt to get DSD directly to the DAC. I thought this is what the Expert series did? DoP looks like PCM, but when it gets to the DAC it is actually the unaltered DSD stream that gets played. I was hoping this would be the end solution for the Phantom too.

[ogs]

I doubt this. There is a lot of DSP processing taking place in Phantom to achieve the end result. Also the specification of the Expert amps say "Built-in DSD / PCM conversion". It might be possible to send DSD through in Expert, but as soon as for example SAM is enabled PCM is necessary for processing. I do not know if DoP is used for DSD handling by Devialet as I've never tried to play any DSD. I'd think that if you run DSD packed in a PCM container through some sort of DSP processing you'd be unable to extract DSD afterwards.

[sekriT]

I just streamed both DSD and DSD over PCM (DoP) to Dialog (hoping that latest firmware update turned on some these features).  Both of them still gives no sound i.e. Dialog does not process these formats yet. I can only play DSx files after converting them to PCM 24/192 before streaming to dialog.   

I think both Dialog and and Phantoms should be able to do DSD and DoP.  But someone (Devialet maybe?) needs to work on it.

[f1eng]

ADH uses PCM, so DSD has to be converted or the bass correction, phase correction, active crossover network, volume control and the 4 AHD amplifiers would not work... Devialet calculations are done with a precision beyond DSD so no audible degradation will take place IMHO.
Don't worry though, 99% of your DSD files will have been converted to and from PCM files used for mixing and mastering, so they are just going back home, as it were.

[jonstatt]

ADH uses PCM, so DSD has to be converted or the bass correction, phase correction, active crossover network, volume control and the 4 AHD amplifiers would not work... Devialet calculations are done with a precision beyond DSD so no audible degradation will take place IMHO.
Don't worry though, 99% of your DSD files will have been converted to and from PCM files used for mixing and mastering, so they are just going back home, as it were.

Yes indeed f1eng and ogs, you are both absolutely right. All of the processing algorithms of course are only written and employed in the PCM realm. So DSD at best, would be "supported" only as far as a file format, and would need to be converted to PCM within the Phantom itself no matter what. That being said, it is quite easy to convert DSD to PCM on a PC anyway if people are impatient to wait for DSD support from Devialet.