@audphile1
That’s not what I was saying, but the confusion may be my fault, dashing off messages quickly late at night. I suggest checking out the lengthy 2001-ish piece I wrote on the topic of optical-disc standards, published in one of the Ziff-Davis magazines, maybe PC Mag?. If you don’t see it, I can look for the manuscript in my personal archives.
Here are the key points relevant to our current discussion. Hope this is helpful:
- I’d deliberately mentioned sending "digital data" over HDMI, not DoP, which AFAIK, is legally constrained to connections like USB, not S/PDIF or HDMI.
- My transport docs aren’t 100% clear, but I assume that it internally converts DSD to PCM before transmission over HDMI. This is not DSD encapsulated in PCM packets, but a true, standard LPCM stream. The T+A DAC then decodes the PCM stream normally through its dedicated PCM signal path.
- DoP, unless it’s been updated in the last 20 years, is limited to DSD64. My transport’s conversion to LPCM, however, can handle much higher data rates. DoP is also relatively susceptible to jitter, with clock data is embedded in the stream itself, while HDMI’s video-ready sync is, all things equal, more robust.
So it’s not hard to argue that, despite an internal format conversion that negates the benefits of the T+A DAC’s dedicated end-to-end DSD signal path, this method is superior to a DoP transfer in some ways. E.g., it offers:
- much higher bandwidth, including the ability to transfer hirez multichannel data. This may be moot, since DoP’s DSD64 limit is the highest data rate defined by the Scarlet Book.
- more robust (although still far from perfect) HDMI clocking
- wider deployment, since pretty much every HDMI-equipped audio sink natively decodes LPCM streams
- compliance with all Scarlet Book and DMCA constraints -- IOW, legal over any digital connection, unlike DoP, which is considered infringement over HDMI or copper/fiber S/PDIF. This is because HDMI has its own end-to-end encryption/content-protection algorithm, called HDCP.
- no need for external boxes & cabling, a la D.BOB.
The downside in my particular setup is that sending PCM to the T+A DAC negates the benefit of the DAC’s end-to-end pure-DSD signal path. However, most DACs, even some of the highest-end models, do the same kind of DSD-to-PCM conversion when decoding any DSD content. It’s not clear how much this compromises SQ in my case – this isn’t a multikilobuck transport – but this is the best solution I’ve found at this price point. And the T+A DAC’s dedicated PCM signal path seems to do a good job with the LPCM stream.
Oh yeah, there’s also a third option for transmitting encapsulated DSD over HDMI, I forget the name now, something like HDMI-DSD or DSDOver HDMI. It’s rarely implemented widely, so I haven’t paid attention.
Bottom line (and this was the only point I was trying to make, so long ago!) is that T+A’s gear can accept hirez digital data from an SACD transport via HDMI without requiring a third-party box, and that the quality of that signal is even superior in some ways to that of a DoP transfer. When looking for a terrific DAC that offers outstanding SQ & connectivity for the price, one should add T+A to the short list of Aurender, Bricasti, etc. candidates.