Originally Posted by edorr
You seem to be confirming that High Rez audio over HDMI is flawed and without something like ARC it is deeply flawed. Also, (mostly because of SSP flaws) a "best in class" HDMI transport won't come close to matching the 2 channel analog out into SOTA preamp for music. Even without your level of deep technical knowledge I full concur based on listening experience.
First of all, you have to realize that everything I write here is just one man's opinion. Like everyone else, I can be wrong about something. I happen to have more experience in many areas of this hobby than most other posters, but I am certainly not infallible!
We are very fortunate indeed that Roger Dressler is participating on this thread. He probably wouldn't have time to do so were he not retired -- he is perhaps the single man most responsible for bringing multi-channel audio to home theater. And if you have read this thread all the way through, you will see several places where he has corrected my mistakes. So in case you needed proof that I am not infallible, there you go.
Second of all, I think it is important to qualify the terms "flawed" and "deeply flawed". Obviously these are subjective, and I tend to approach things from an engineering design perspective. So let me condense my views to a few short points:
a) HDMI is "flawed" for audio because the connector was designed before the sysstem was specified. They should have sent a separate audio master clock, but thought that it was more important to have a reserved pin (which is still unused, by the way). The penalty is that (all else being equal) HDMI will have higher jitter levels than S/PDIF, which is already a convenient, but low performance, way to transmit digital audio.
b) The HDMI committee partially addressed their oversight by permitting
, but not requiring, Audio Rate Control. Audio Rate Control allows jitter levels to be dramatically reduced, albeit at a relatively high cost. The system is complex and expensive to implement.
c) Nearly all existing SSP's are "flawed" because due to cost and space constraints, they use high-feeback op-amps in the audio signal path and single-chip op-amp-based IC volume controls. There are a few exceptions. The Theta Casablanca uses a system of FET switches and metal film resistors for its volume control. I believe
(but am not sure) that the audio signal path is fully discrete, although it also uses feedback. The Levinson No.40 has a different kind of volume control. I believe
(but am not sure) that it is the MDAC style of volume control that they used to use in their No.38 preamp. I am unsure of the other details of the No.40's design. The original version was released shortly before the company imploded. I have heard snippets that the version put back into production a couple of years later had some changes.
Originally Posted by edorr
However, this leaves me with one question. Why - given the foregoing - do you expect a standard Oppo 83 over HDMI into the forthcoming Theta casablanca III HDMI to sound better than say a Marantz UD9004 into the six shooter (as you stated earlier in this thread).
I would expect the Oppo/Theta combination to sound better based on two things:
a) The Six-Shooter is a great volume control, but to the best of my knowledge, is identical to the one that is already inside the rest of the Casablanca. The only reason they made the Six-Shooter was because they didn't have any way to send certain types of data digitally, such as "DSD", five years ago. But now they do -- HDMI.
So there should be little, if any, difference in the sound quality of the two paths in the Casablanca from that source.
b) One can take a jittery signal, such as HDMI or S/PDIF, and by throwing money at it, reduce the level of jitter. The more money you throw at it, the lower you can get the jitter. Theta has been building digital products for over 20 years and has some of the best jitter-reduction circuitry around.
So to answer your question, I believe that comparing the two combinations you have proposed, the volume controls will be essentially the same. So the question is whether the improved DAC's and audio circuitry of the Theta are enough to overcome the added jitter levels of the HDMI connection. And in this case my prediction is that they will be.
But, as I said before, that is just a guess. The only way to know is to listen. Then you will know. But also if you go with the Oppo/HDMI solution, you will be broadening the capabilities of your system. If you go with the Marantz/Six-Shooter solution, you will be going down a dead-end road. I don't think that there will be a lot of ways to improve that system, as I don't think that there will be newer and better players made with multi-channel analog outputs. So I think you will have better upgrade options in the future by adding HDMI.
But that is all just supposition and (educated) guesswork on my part. You are the one who is going to have to live with this equipment. So before I spent many thousands of dollars, I would definitely recommend listening to both options and then deciding.