Seandtaylor99 - I would not put the onus on either the DAC or the Transport. Either can have very low jitter. However, the closer you get to the D/A chip with a low-jitter clock, the better the result. The problem is that most modern DAC chips dont use the classical "word-clock" to actually do the conversion. They more often use the bit-clock or even the master clock, which are much higher frequency. This is why I prefer the I2S interface. It enables all of the clocks (SCLK, MCLK and L/RCLK) to be close to the D/A chip. If the source of these clocks is low-jitter, then mission accomplished. This is what I do in my Pace-Car.
Steve N. |
Jsadurni - I have a couple of Off-Ramp customers that are using the Altmann DAC. They seem to like it. I dont really understand what this JISCO thing is. I have reports from some that it is better turned-off. Others seem to like it on. Looking at the parts and board design I'm not impressed and evidently some digital signals pass through a toggle-switch? It may sound good though. Never heard one. The battery power definitely helps.
The only DAC that I'm aware of that uses a true jitter rejection technology is the Lavry. This is sound technical design. Interesting feedback from a customer that upgraded from a Audiophile USB to an Off-Ramp Turbo 2 though. It sounded better, more focused. Maybe it does not reject all jitter? Still one of the better designs available commercially.
Steve N. |
Jsadurni, I certainly don't claim to know the answers to this problem, but here is another DAC manufacturer who says that all transports sound the same, provided they are slaved to an accurate clock in the DAC
http://www.lessloss.com/about.html
And another paper by Dan Lavry, maker of pro-audio DACS (that are very highly regarded)
http://www.lavryengineering.com/white_papers/jitter.pdf
It certainly seems to me that the answer to jitter lies in a properly designed DAC, not in the transport, but I'm always open minded, and if anyone would care to step in with a technical explanation why this is not the case I'd be very pleased for them to do so. |
I dont know about ESP, but my jitterous transport is scary!!!
Maybe Saendtaylor99 is on to it with the input signal:
this is from the Attraction DAC: "The high integration of unique features was achieved by the development of a special digital receiver-chip (Altmann R16)."
"The digital input signals are recovered with extremely low jitter as they are generated by custom made voltage-controlled crystal-oscillators (VCXOs) and employ the UPCI (Ultra Precision Clock Injection) technology."
"A switchable JISCO-function (Jitter Scrambling Decorrelator) further increases sound quality as jitter-components from the DVD-A or CD player are decorrelated before being ultra-precision-filtered."
"
http://www.mother-of-tone.com/attraction.htm
very interesting reading...
I havent heard the DAC but it has rave reviews, and its really nothing fancy, a nonos DAC and an opamp...yes battery power supply.
Steve do you know which other dacs use this technology?
Best, |
How about ESP?? (My name also happens to be Alex ;-) |
Still waiting for Alex's response: If it's not jitter what is it????
DSP??
Steve N. |
"my main point, the question of whether jitter alone is really the whole story aside."
Zaikesman puts it correctly, our ears are telling us jitter is not the whole story, maybe we have to unwrap the whole "DNA" chain before we know for certain, its good to have people like Alex and Steve looking into this.
Seandtaylor: cheers man :) |
Zaikes ... I also use a Monarchy DIP. I wasn't critcizing your choice. It's a great product for the price.
Jsadurni, "brute force and ignorance" is a term for using over-specified products to achieve an end. I was not accusing you of being ignorant. |
Right, I never said the DIP eliminated jitter, I'm sure it can only reduce it. Its low price shouldn't be held against it, and appears very well made inside (though could be better shielded -- what it radiates makes it necessary to keep it a safe distance away from my phonostage). It's widely regarded as effective with independent test measurements to back it up. It does have iso trannies on the inputs and outputs. The "24/96" version I own uses the CS8427 chip for the PLL, not a SRC, and reclocks. Steve says that a completely effective unit doesn't exist, except maybe his own which isn't for sale yet, so I can't feel too badly about taking advantage of the cost-effective DIP. And if that's true, then it should also be true that there's no box out there which can render the differences between transports unimportant, which was my main point, the question of whether jitter alone is really the whole story aside. |
Seandtaylor99: What the Genesis does is a buffer, the data is read and sent out the buffer which then reclocks it, this approach is used in modern DVD transports which also buffer and even get to re-read the tracks before playing them: been there done that, a good transport beats it hands down IMHO, If you want to believe you can do with a DVD player and justify it with mental fabrications its fine, just leave my immense ignorance out of this.
Adding an external jitter device with extra cables creates more jitter, a theory I would be comfortable with would be a one box player with a great transport, separate power supplies, a very good clock, and the DAC inches away from transport and clockÂ…theory; my ears tell me a good transport and DAC is already very good!
Steve: I admire how you really stand behind the products you manufacture, cheers! |
Thanks for the reply. An additional feature of the Genesis (and the 518, which is a dual PLL, not a true reclocker) is the ability to add dither, and play with the word length. With my limited DSP background dither would appear to be a very interesting possibility, especially since most modern DACs are 18/20 or 24 bit, so the dither can easily be added without reducing the original word length. |
Seandtaylor99 - I have customers with these. I have to hear it to believe it.
I've heard a true reclocker, my own Pace-Car. It is still in debug, but amazing sound.
Steve N. |
Steve, the closest to what you suggest "A true re-clocker with good ground isolation" would appear to be the genesis digital lens. (I've never used one, but would like to have a play with one). |
Zaikesman - I would be wary of drawing conclusions about jitter reduction from a Monarchy DIP. It certainly helps, but as you say, is far cry from elimination of jitter. Even the expensive Big-Ben, which incidently works much better is not jitter insensitive. A true re-clocker with good ground isolation should make even the cheapest DVD player sound like a million bux. Unfortunately, it does not exist.
Steve N. |
Alex - You claim that ther are other "Factors" than jitter. What are they?
The ability to read disks without error is a capability of even the cheapest $50 transports. What else is there than jitter?
I suppose one other thing could be galvanic isolation, such as with a pulse transformer, but again, even cheap transports have transformers on the digital out.
Edge-rates vary quite a lot between transports, but again, this is manifested as jitter.
Steve N. |
Jsadurni wrote:
"Are you saying that the only difference between a good transport and a bad one is in the High frequencies?"
No, the jitter is the difference. The HF are the most noticable effect of jitter.
Steve N. |
JSadurni the benchmark uses an ASRC (asynchronous sample rate convertor) to "remove" jitter. It is well accepted that this method does not remove jitter effectively, and so it does not surprise me that the DAC1 is sensitive to the transport.
"This is high end, we need the best transport and the best DAC with the best reclocking available!!!"
Maybe a brute force and ignorance approach is needed, but I am not convinced that this is the case. |
I had the Benchmark dac in my system and it is VERY sensitive to transport changes!!!
This is high end, we need the best transport and the best DAC with the best reclocking available!!!
This jitter thing seems to me like when Solid State replaced Tubes because the only factor people where looking at was WATTS, we later noticed different. |
Zaiks ... the Monarchy is a bad example of a jitter buster. It's priced very competitively, but it either uses a PLL or an ASRC chip to reduce jitter. It does not eliminate the jitter of the transport.
To really eliminate the jitter you need to buffer data to RAM and reclock it with a low jitter oscillator. There's an article about it on the Lavry engineering website.
So it's not surprising that you can hear transport differences with the Monarchy, just as people claim to here differences with transports with the Benchmark DAC1 (also an ASRC).
Alex, you're not the first person to tell me that there are other differences, and also not the first person to not tell what the differences are. If it's a business matter to keep secret then I understand. I would genuinely like to know. It seems unlikely to be bit errors, since a $20 DVD_rom drive can install a bit perfect copy of Windows XP, reading the disk much much faster than a CD would need to be read. (And the OEM purchaser of such a drive can source the main drive components for only a few dollars). |
Without reading through all of the preceding responses, let me just state (as I have before) that no, contrary to Seandtaylor99, my experience is that a reclocking device will not necessarily render insignificant the differences between transports. Why this is, I cannot tell you with certainty. I can only report that although I find my Monarchy DIP 24/96 to be an effective device for improving the final sound (and anti-jitter box test measurements linked on the Monarchy site seem to indicate that it's one of the more effective such devices at doing its job), it doesn't somehow obliterate or equalize the audible differences between transports, which remain as plain as ever. In fact, it's entirely possible (and seems logical to me) that it actually exposes those differences a bit more clearly, by granting basically the same degree of improvement -- and hence increased resolution -- to each of the sources paired with it (or, if you prefer, to the DAC paired with each of those sources). But whatever the case, I've found that using this otherwise fine unit in no way enables me to consider transport selection as noncritical -- a nice wish, but regrettably, no go en mi casa. |
Pardon my ignorance. If the only difference between a good transport and bad transport is jitter, does that mean the best and most expensive transport will have an extremely low jitter?
IF jitter is the sole parameter in affecting the sound quality of any transport, can we assume ALL transport(including the most expensive ones) will sound similiar if the issue of jitter is addressed successfully? |
"The only difference between a good transport and bad transport is jitter."
I wish this was the case but, unfortunately, it is not! Jitter is very important but there are other very important factors as well.
"So you have a choice. Buy a low jitter transport (often very expensive) or buy a reclocking DAC, or a reclocking device to sit before your DAC."
I wish this was the case again! And, according to you, where all the jitter from the transport goes when you implement your re-clocking devices? When you stick your head in the sand the world disappears, is that it?
In general, it is not a good idea to use DVD players for transports (unless serious upgrades are applied), but there are few DVD players that can do the job. Sony ES models for example.
Regards,
Alex |
The only difference between a good transport and bad transport is jitter.
So you have a choice. Buy a low jitter transport (often very expensive) or buy a reclocking DAC, or a reclocking device to sit before your DAC.
Personally I feel you get much more flexibility from a reclocking device or DAC than an expensive transport, as you can now feed digital signals to it from any transport, from your PC, from a squeezebox, and the sound that comes out will be relatively immune to the quality of the transport.
On the other hand if you buy an expensive transport it will probably sound great, but won't help at all should you ever want to add a squeezebox.
And my final concern is that the transport is generally the least reliable part of digital audio, so I'd rather not spend thousands on it. |
Steve "the Transport primariily has a impact on the jitter. The jitter has a sonic signature that mostly impacts the high-frequencies and the dynamics of the HF"
Are you saying that the only difference between a good transport and a bad one is in the High frequencies?
If this statement is true, I will have to ask what transports have you listed to in your system? |
Astrostar59 - what you must understand is that the Transport primariily has a impact on the jitter. The jitter has a sonic signature that mostly impacts the high-frequencies and the dynamics of the HF. The DAC on the other hand can have an impact on the entire frequency spectrum as well as dynamics top-to-bottom. Noise and distortion are also DAC related. The DAC can also add jitter. Given all of these impacts, I would have to judge the DAC the most important with the Transport/digital cable next important.
Steve N.
Empirical Audio
Manufacturer |
"The wisdom handed down to me from one of the most respected engineers and manufacturers of tube gear was expensive transport and modest dac make for a musical presentation and the other way an audiophile presentation."
This is not wisdom IMO, it is a result of some limited anecdotal evidence. The sound result depends entirely on the designs of the individual components and the parts used therein. No conclusions like this can be drawn IMO. And I would be wary of who you consider wise.....
Steve N.
Empirical Audio
EE with 30 years design experience |
Hello you guys!
Nice responses to my post. It seems that there are 3 schools of thought here. Transport is most important, or DAC is or both. I am wondering if the combination of certain gear is also playing a role here. I mean, any electronic in the chain WILL change the sound, even if its just an input impedance or waveform reshape, however suble. It will be audible at the final presentation.
I like the idea of solid transport, and tweakable DAC, that is DIY DAC, with black gates, valve change and silver parts to add later on. It will all add to the sound.
Check out Audio Note kits 2.1 DAC with upgrades. Great value for money and right up there with the best I reckon.
The other thing to think about with transports is in my experience the laser dies after 5 or 6 years. Ok, long time, but something to bear in mind if the transport is in 4 figures. |
Some designers and engineers of digital components opine the transport is more important than the d/a. |
yes, it matters big time! using audio note dac3 sig and had mbl 1531 . Bought Oracle 2000 transport and watch out!!! Same phillips pro rig but the oracle with suspension outclasses the 1531 cd player .(using dig out)
The wisdom handed down to me from one of the most res[ected engineers and manufacturers of tube gear was expensive transport and modest dac make for a musical presentation and the other way an audiophile presentation.
In my opinion this is right on... that is why I bought the two pieces and am hunting for a good cable.(silversmith?) |
Very interesting on the NON OS DAC's and insuating that the Transport is not a huge factor in reproduction of sound. In my past experience and present, the transport makes a HUGE difference. I currently use an Electrocompaniet ECD-1 (which is NOT a NON OS DAC) and you can tell a huge difference from transport to transport as I have tried several combinations and digital cables for that matter. Very interesting post..
Chris |
Seantaylor is right on the money with the reclocker and NON OS DACs. The difference in sound for the better when using a reclocker with these units is undeniable. Astrostar59 ..you should try one just for fun. The Monarchy DIP, Digital Lens, GW Labs and a few others will make a significant difference with the old school Dacs. I'm going to jump on this Computer transport trail soon and hear what it's all about. I'm thinking a media center type computer like the SYS MediaMax, could put me where I want to be. This will eliminate using a basic transport,cd player,DVD player and DVR player all by giving you the ability to run the entire system with one remote or keyboard..which is exactly what I want to do. My thinking is..I'd rather go this route than spend thousands on a Slim Device Transporter or dedicatd transport with no where near the features or expandability. |
I believe in very expensive transport and cheap DAC.
I have a Forsell Air Reference transport hooked to an EAD 7000 III DAC
I dont believe in the "Reconstruction Theory", jitter is all that matters, so the Transport can send any crap to the DAC and the DAC will "Reconstruct" the signal with a good clock!!!
I just dont buy it!!! |
Jitter is the difference in both Transports and digital cables. Jitter is also a problem with commercial CD disks. Rewriting a disk with a low-jitter writer can be equivalent to $1200 in mods to the transport or a $600 digital cable. See these articles on the subject:
http://www.positive-feedback.com/Issue14/spdif.htm
http://www.positive-feedback.com/Issue22/nugent.htm
As you can glean from the articles, changing transports is not really the road to low jitter, computer audio is.
Steve N.
Empirical Audio
Manufacturer |
Reclocker... interesting, I already myself have too much power cord cost, and cable cost to add more in between.. I am not so sure you can't get a transport with a upgraded clock or better one in the first place to fore'go the excess cables and conversions adding a third unit to the digital chain, but I have not had these issues so maybe it is a good path. |
From personal experience I believe the single most important issue is jitter. I don't believe that bit errors are a significant source of sonic degradation, or that there's significant performance difference in the area of bit errors.
If you have a well designed reclocking DAC then I think that the transport does not matter. (Think Lavry, and to a lesser extent Benchmark DAC1).
If your DAC derives its clock from the SPDIF, AES EBU, or (horror) toslink input then the transport will matter much more.
I'm pretty certain that your audio note DAC does not reclock the data at all, so I would expect it to be quite sensitive to the transport. If you were to put a quality reclocker in between the transport and DAC, such as a Meridian 518, or a Genesis digital lens, I think you'd find the setup fairly immune to transport quality. |
Transports do matter, I'm currently using a highly RAM modified CEC TL51X and it sounds COMPLETELY different than other transports I've tried.
I think what may give the, transports don't matter myth, some legs is that in my experience, even very inexpensive CD/DVD players can make good transports.
The sound quality of some very low end DVD/CD players has gotten insanely good.
It's when you try the get that extra 15 percent or so of sound quality, that you need to step-up to what is usually a much more expensive transport.
You also need a system capable of passing on the improvement.
Another myth I believe exist is with the "digital cable" used to connect the transport and DAC. Although a number of inexpensive cables sound good. If you want the best, it's going to cost you. And yes, it makes a big difference. |
The two biggest factors that I have heard effect a DAC / Transport combo is the Transport And digital cable.. Both pretty much as important from my many trials... A close next would be the Power cables on both units.
Some transports sound more syrupy, some very stringent or thin, some with Heavy weight in the bass and good solid dynamics. It will depend on the combo, but to your question, yes big things can happen for better or worse when A-B testing transports against each other in the same system with same cables, sometimes night and day better or worse in certain areas or with certain types of music.
Myself and a friend tried a few DVD players, Stable platter transports, Good single disc dedicated transports, and even CD changers in some direct compares.. We have normally found the dedicated transport built machines do have some extra magic to them..
Cheap dvd players do implement several other un-used circuits for video etc.. in them and sometimes sound pretty good, but not always competitive with an actual transport. But I have not heard it all so that will be your own listening to determine what you need. They can sound quite different just like putting a totally different amp in front of your speaker, same as what transport you got in front of your DAC. |
