I am not familiar with the Black Dragon DAC but if it uses a true HDMI port then you cannot connect to a PWT using an HDMI cable. The PWT, PWD, DS and NuWave Phono Converter use HDMI cables so send I2S signals but they are not HDMI compatible.
EDIT: I just looked up the Black Dragon and it does use the HDMI connector for I2S so it should work as long as the pin assignments are the same. Others on the board who have experience with this might be more helpful.
It’s not the cable, but I don’t believe that the DAC in use is set up to accept the I2S that the PWT is sending out. Between the PWT and the DS or PWD any HDMI cable works, but that is because the receiving end can accept the I2S. . . .
I just looked at the specs for the DAC and it does say DSD/I2S over HDMI. . . may not use the same protocol as PS Audio has written. Looks as if it could or should work otherwise. . . hopefully you’ll hear back from the support staff.
There are HDMI cable testers, but the only way I know to test a port is to connect it with a good cable to something that you know responds to HDMI. Not very helpful in this case.
Please let us know what the support people from each company tell you.
I spent some time searching for information on the Black Dragon. I was not able to find enough definitive information to decide anything for sure, but I did find that there are some differences in the connector pinout (specifically, the data, LR clock and master clock lines have the phases inverted. Also they add a 5V detection line that PS Audio does not use), and some missing information about clockrates. The operation manual did not say that there were any configuration options in the BD to adapt to the PSA format. From this it appears that as you have discovered experimentally, the Black dragon I2S is not compatible with the PWT I2S.
The Hydra Z operators manual describes jumpers that can be set to configure the I2S output to match the PS Audio clock rates and polarities, or to match the standard used in the Black Dragon. I did not see a similar description in the Black Dragon manual, so I would assume it does not have the same adjustability.
Dave P. said
I spent some time searching for information on the Black Dragon. I was not able to find enough definitive information to decide anything for sure, but I did find that there are some differences in the connector pinout (specifically, the data, LR clock and master clock lines have the phases inverted. Also they add a 5V detection line that PS Audio does not use), and some missing information about clockrates. The operation manual did not say that there were any configuration options in the BD to adapt to the PSA format. From this it appears that as you have discovered experimentally, the Black dragon I2S is not compatible with the PWT I2S
Update! The Black Dragon is not compatible with my NPC via I2S either but according to the German distributor of Audiobyte it can be made compatible. As far I have understood this happens by deactivating that detection line. It is a service for free for BD customers. (The Hydra Z doesn't have this detection line.)
Listening to the BD/Hydra Z via I2S that was the best I ever have heard at my home. Especially DSD I have enjoyed so much. But… the BD can not replace my Oppo HA-1 as a preamp. Soundwise the BD is a winner but concerning convenience, haptics it can not beat the Oppo. Now I wonder if I should run the BD beside the Oppo or if I better venture the big step to the DS DAC. Decisions, decisions…