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In Reply to: RE: It depends on the DAC posted by Scrith on March 30, 2014 at 10:29:47
In the line for "perfect DAC", take the number, and stand behind Tony Lauck.
Follow Ups:
I never claimed that a perfect DAC would provide magical transportation to the original recording sesssion (assuming that such a thing even existed). All I said was that it was possible to build a DAC whose sound would be not be dependent on the computer equipment upstream. By this definition two possible (not necessarily convenient or practical) solutions come to mind, but these serve as an existence proof of the concept:1. The Brick DAC™. This product is 100% guaranteed to provide complete transport independence. All computer transports sound the same. Indeed, all recordings sound the same, whether Debussy or Death Metal. One can purchase these inexpensively at one's local Home Depot, but some skill is required to understand how to (not) attach appropriate cables to the device. It is likely that this product is also "cable independent" but YMMV.
2. The SDcard buffered DAC. The data from the computer is recorded on SDcard. The link to the computer is disconnected and the computer is powered down. Then the SDcard DAC plays the data stored in the SDcard. It is reasonably certain that what you hear will not depend on anything in the computer that happened other than the bits that were sent to the SDcard. Whether or not what you hear sounds good will depend on the specific product. You might try the Mirus if you are a fan of SABRE chip based DACs. Some people say that the USB input and the SD card on this DAC sound the same, but this could be nothing more than marketing hype. The Mirus does not include an SD card writer, but these and SD cards are available at Amazon.com. You can use Win32DiskImager.exe to write your audio files onto SD cards. There may be some user interface and latency issues, but I think it reasonably likely that this approach will achieve computer independence, although I don't have hands on experience with this the Mirus so I can't say how good it might sound.
Personally, I recommend The Brick DAC™. It has two great advantages: there is no need to spend tens of thousands of dollars on amplifiers, speakers and room treatments. Also, if installed properly (there is no other way) one can be assured that neighbors will not complain about loud music. :-)
By the way, in GF(3) 2 + 2 = 1.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Edits: 03/31/14
BTW, that name is taken by a real DAC already, so better come up with a different name, let's say The Dumbbell DAC™.
Regarding SD card player - I'm sure you realize, better than many, that combining transport and DAC in one chassis does NOT make DAC independent of transport, and doesn't tell you anything about resulting sound quality. Not too different from a stand-alone CD player - how many "perfect" ones have you encountered?
The definition of "transport" is arbitrary, which is why I believe my post used the word "computer". As I mentioned in a later post, an SD card itself might be said to contain a "computer" and for that matter my Mytek DAC (which does not contain a transport) also contains a computer.
Obviously, what matters is how the system sounds. If DAC 1 scores a 3 on sound quality with transport A and a 3 on sound quality with transport B, then it is transport independent. One would definitely prefer DAC 2, which scores a 5 with transport A and a 9 with transport B, even though it is not transport independent. And, depending on pricing, one might even prefer DAC 3, which scores a 1 with transport A and a 10 with transport B.
I have no way to evaluate CD players as being perfect, as I do not work in the marketing department of either Sony or Philips. I do not believe it is possible to achieve perfect sound with any PCM format of lower resolution than 768/20 or DSD of lower resolution than DSD128. However, I have heard 192/24 and DSD64 recordings that sound excellent, certainly better than any consumer level tape or LP playback that I've heard.
The gold standard for converter perfection is comparison of a live microphone feed, vs. a live microphone feed passed through an ADC -storage- DAC loop. (The storage part is needed because without it it is possible for jitter in the ADC clock and DAC clock to cancel each other out. For evaluating other qualities of the DAC it may be more convenient to eliminate the storage portion.) The problem with this approach is that the ranking of DACs will differ if the ADCs used are different. There is no technical standard or specification of which is correct, and seldom does one get to even know what the equipment used was in making a recording. Because of the lack of these standards, the entire concept of perfection in a DAC is pretty much empty. So I would say, forget about "perfect" DACs. However, it would be possible to tell if a great sounding DAC has "perfect" isolation, by garnering a large collection of poor to excellent transports and listening to how the DAC sounds with these. Of course one would need a suitable set of recordings that would provoke various artifacts that less than stellar performing products might produce and a sufficiently good analog and acoustic back end.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
That are your own inventions.
A transport is not arbitrary, it is clear & defined to everyone but you. The computer is a transport. The SBT is a transport. There are different kinds of transports; a PC is a different kind of transport than a disc spinner. Transports can have the qualities of goodness & badness. Anything that delivers a digital signal, (no matter what the delivery process is), to the DAC section, (no matter where that DAC section is located), is a transport.
As we/they violate computers into exclusive music playback devices, we limit the computer to a music playback, digital file transport.
Once we stop agreeing on the meanings of our words, conversation & language breaks down & becomes meaningless.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Sorry you were confused. Unfortunately, computer audio technology is complicated.
The definition of "transport" and "DAC" represent the division of commercial products into components, e.g. a one box "CD player" became a two box "tranport" and "DAC processor". Such definition evolves over time with the development of technology. For example, back in the days of reel to reel tape machines, a tape deck often consisted of a "transport" and the electronics, This was the start of definition and it carried over into CD players and later two box CD players. With solid state storage electronics this mechanical-electronic division becomes inoperative since there may be no moving parts at all associated with media storage. When one starts talking about more complex networked systems then it becomes even more complex because the control function of the traditional transport (e.g. start/stop, ff/rew) may be completely separated from the device that is generating the bit stream and there may be distant devices that hold media storage that are serving as file storage, not media transport.
Given this situation, I think it best not to niggle about details. The context of my post was to make it clear that my understanding of computer audio was that it included all of the components that would affect good quality sound out of a computer based audio system and hence that my comments suggesting one would be better advised to concentrate on making a DAC immune (or installing reclockers or other isolation devices) properly belonged in this asylum, and not some other one such as Hi-Res or Digital. My intent has been to discuss getting good sound out of computer based systems and not to disparage them, so I do not believe my comments are out of place, as some people have implied.
There is also a question of what constitutes a "DAC section". One needs to be quite precise about the engineering details of this if one wants to have a system that is immune to jitter. Since the clock that maps the digital bit stream into an analog waveform is obviously part of the DAC then it should count as part of the DAC. However, if this clock actually controls the rate (timing and pitch) of the music one could say that the clock is actually part of the transport. So the definition of "DAC section" gets complicated and subject to debate unless there is a precise definition (which many non-technical audiophiles probably wouldn't understand) and detailed engineering design details (which are seldom if even available for commercial products).
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Definitions really don't evolve that much. They can improve, by further excluding the possibiity of other things.
You make some good points. But, as with the clock, there are players that have no master clock, but clocks built into the DAC(s).
Being precise about engineering details has nothing to do about whether something is a DAC or not. "Immune to jitter" is a laudable goal: but has nothing to do with being a DAC or not. But it has something to do with being a good DAC. There is nothing complicated at all about the definition of a DAC. It either converts the digital signal to analog, - or it does not. How good it does this, or where the Master clock is located, has nothing to do with it. DACs were around a while before computer transports.
If developers are having issues with computer transports to their, (or a), external DACs, then they have issues with the computer as a different kind of transport. Or, the type of "older" DACs that were optmized for motorized disc spinning transports, have to be modified to accept the different kind of digital signal that comes from a PC. This is the reality that we've seen from Wavelength, Ayre, etc. DACs sounded GREAT (better) before designers/people used them with computers.
Blaming the DAC for a noisy mainboard, power supply, hard drives, bus, etc. is misplaced blame.
We talk about all of this stuff in a context. That context, IMO, should include different experiences that will help us develop a better reference. Getting a wide range of viewpoints and perspectives, only helps. If you have listened to a 6 box Wadia disc transport with separate DACs, (for example), you will have the ability to make comparisons between a fully optimized computer based transport and DAC. Especially if you take away the Wadia disc spinner and plug your PC in.
Computers are commercial products too. And those products have never been optimized for audio. So therefore it is up to us. Since DACs have been a part of excellent audio playback for years before PCs, it stands to reason, that we cannot cavalierly place blame on the DAC as being the stop-gap to good sound. This is especially true given the validity of point to point wiring in the high end. The experience from manufacturers, and consumers has been, (rightly), to tweak the computer to the point where it is no longer one: making it even more of a "transport." No matter the quality of the DAC, Pure Music is still going to sound different than Amarra.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
nt
I mostly agree with what you said. As to the computer creating noise in the motherboard and affecting the DAC, it might also affect the preamp and amplifier. One can consider this possibility by running the computer while playing analog source material and seeing if there is an adverse effect. One can also try various combinations of how these effects might get coupled, e.g. signal cables out of the computer, power cables (if one has some long extension cords that can go to other circuits), etc...
Ordinarily, the signals on the motherboard are supposed to remain inside the computer and not appear on the outside. We know that this is not the case, as can be easily seen by using a battery powered portable AM radio. This is another useful diagnostic tool that can be used to trace down these effects. I also know that these signals vary according to what the computer does, e.g. the frequency of interference alters according to the loop timing (e.g. as controlled by buffer sizes). In decades gone by people used to play music on AM radios by running special software that timed these loops.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Resonessence Labs has some interesting DACs. On one of their webpages they show a 256GB SDXC card which is a good amount of capacity in such a small package, but still rather expensive at around $450 +/-.
If I had an extra $5000 USD it might be fun to give it try:
Resonessence Labs claimed a while back on their web site that only a few audiophiles had been able to hear a difference between the SD card and the USB interface, with an older firmware rev. They also claimed that after a certain firmware rev, none of these people could hear a difference. I don't doubt this, but I'm sure that several of the vocal inmates here have yet to hear this product. Personally, I'm a bit suspicious of SD cards themselves. There may be the same "bits" stored in them from the normal user interface, but these bits may be physically stored in different places due to wear management algorithms. SD cards contain a microprocessor and some hackers have found how to program this processor for nefarious purposes. It would not surprise me that two "bit identical" files on an SD card might sound different, unless there's been a very good job isolating the SDcard reader and processing from the clock, DAC, IV and analog output circuits.
Another DAC that some customers report is immune to its digital input is PeterSt's Phasure NOS-1. Its physical construction lends credence to this being a design goal. This is another DAC that I'd like to hear.
Today, I am having a one day special on an audiophile edition of the Brick DAC™. I am taking pre-orders on this product. The product is priced in bitcoin and will be a bargain at 4.2 BTC. Payment in bitcoin must be received no later than 12:01 AM, EDST, April 2, 2014 to reserve your place in the first production batch. Payment should be sent to 1M2AntDLHvmshSHge5DBL2v4sVHCS45hUv
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
nt
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