artto

Hi there Tranz. Yes, but I2s was developed for internal connections inside of the CD transport/player, wasn't it? And a few companies have tried to exploit this to external connectivity. IMHO, one of the weak links in the whole process is the CD/DVD/SACD/whatver disc, the software. That's the source component that needs to be eliminated. It's the source of many problems. A laser (or multiple lasers) reading microscopic interleaved pits on a continuously variable speed spinning disc - which in itself has imperfections, both physical in the manufacturing process as well as damage from physical handling, dust & debris, etc. The disc itself isn't spinning perfectly flat either. There's a lot of issues with this digital "spin-off" from a phonograph record. If it weren't for error correction this stuff wouldn't work at all. But if you can eliminate the mechanical software component, you immediately eliminate any issues, potential or otherwise, from the equation. By using the computer memory as the source for playing the audio file, and using HDMI, no sound card, with all of it's associated problems is required. That's the point of using a true direct digital amplifier like the NAD C390DD. I don't want to sound like a salesman for NAD, but what NAD co-developed with Zertex Semiconductor fundamentally changes everything. The C390 is essentially a DAC amplifier, but with one essential difference that I have yet to see in any other product, and that is "direct digital feedback". This is what really makes this technology shine. With analog, feedback is actually detrimental to music reproduction, it looks good on the test bench playing steady state sine waves and such, but with analog how can one apply feedback directly to the signal path when the signal in music has already changed? With digital that's not the case. The signal can be buffered, held for a moment, compared, corrected, and sent on it's way. For the moment, since it's patented, if someone wants to do the same thing they'll have to find another way of doing it without infringing on NAD/Zertex patent rights. Even NAD's older & more expensive M2 doesn't have HDMI although it has the same direct digital feedback technology. The white paper is quite an interesting read. In my opinion, the fewer connections, sample rate conversions, processing, etc one does, the more faithful the signal. HDMI nay-sayers are living in the past. TOSlink/SPDIF are now 30-35 years old. That's ancient in the electronics world. I hope the vacuum tube guys don't jump into the fray here. A couple years ago I would have agreed with them. Keep in mind that most "digital amplifiers" are not true all-digital amplifiers. There's a lot analog going on all of which are susceptible to the usual distortions, noise, RF, EMI, etc that conventional analog amps are. Any way, that's my two cents. Thanks for listening

I have been using HDMI for audio only music application since spring of 2013. At that time I was making major changes in my audio system, the biggest changes I've made in decades. This included deploying Danley Sound Lab SH50 speakers, four Epik Empire subs, and moving to all digital throughput from source through amplification. The new amplification I chose was the NAD C390DD with both the optional analog/phono and HDMI modules, which replaced my McIntosh, Audio Research, Luxman MB3045 & Wright Sound Lab 3.5 Mono 2A3 SET. They all sound dull, opaque and grainy in direct comparison to the C390DD. One of my source components has been a Sony XA5400ES SACD player which has HDMI outputs. I wanted to eliminate the spinning disc/optical reader part of the equation and its inherent requirement for error correction so I purchased a laptop PC for dedicated use as a music server using J River Media Center. The laptop PC's HDMI output connects directly to the C390DD HDMI input. HDMI verses USB: A few years ago there was much argument about HDMI not being up to the task of high quality audio primarily because of digital jitter. In the audio domain this was primarily due to the fact that in HDMI, sync was carried via the video signal. Obviously, if no video signal is present this would create a sync problem resulting in much higher digital jitter in the audio domain than asynchronous USB. However, starting HDMI 1.3a Audio Rate Control (ARC) (not to be confused with Audio Return Channel) was introduced. With ARC the receiver (such as NADC390DD) is the master clock, essentially taking over timing control of the source component such as the CD player or computer. Digital jitter is virtually eliminated, certainly much better than an asynchronous system such as USB. This also allows for direct higher sample rate without the need for sample rate conversion which in itself also introduces its own set of artifacts due to error correction and interpolation. I hardly ever use analog anything any more (except of course the speaker driver's voice coils). To me this is so superior to what had been using, in a large acoustically tuned dedicated listening room no less, not to mention the convenience of instant access to 1000's of albums/recordings at my finger tips using a small tablet as a remote control for the laptop. I spend much more time listening to music instead looking at CD or LP spines trying to read the titles or religiously preparing the vinyl and stylus for playing and then putting the recording back in its place. Nothing to worry about wear & tear with each and every play, no more vacuum tubes to gradually wither away, essentially no error correction required as the data is simply being read bit for bit from a file in computer memory. Its the shortest, most highest fidelity path I've encountered. And after attending many, many audio shows with systems costing upwards of $500K or more and visiting many audiofile's systems I can honestly say this is as good as anything I've ever heard at any price. It's like having the best of everything I like that I've heard, without the limitations or drawbacks of any. And as others have mentioned, yes, there is a large cost to license, implement and sell HDMI, at every point along the chain. Most high-end manufacturers aren't really making that much money. Their components are too costly to sell a large number of units. And then there's the copy protection issue. If you can get around that with the right set of components and use HDMI for your digital audio connectivity I highly recommend you give it a try. But remember, if you've got anything analog in the signal path (and that includes linear digital amplifiers), you're not going to hear what a true all digital throughput system is capable of.