Reference Transports: An overall perspective

Bombaywalla, ALL CD/DVD/SACD players have a sled with linear tracking for the Laser, except for the famous Philips "swing arm" transport which is now obsolete. The big VRDS-NEO and some newer Philips transports are using a combination between radial and linear tracking where the focusing lens is "suspended" on magnetic field. Since this type of “suspension” is inertia-free, it is the fastest and most accurate reading technique available.

You CAN NOT prevent the disc from wobble, especially with higher than x1 rotation speeds when SDRAM buffering is used, without having a FULL disk support on the top (or bottom in the case of Pioneer "Stable Platter" system). With the Audio Desk Systeme Lathe you're talking about, you can balance the disc and prevent from vibrations caused by eccentricity, but NOT wobbling.

From what I know, the Esoteric VRDS you have in your Wadia spins at x1. The VRDS-NEO spins at about x10 using a large SDRAM buffer from which the data is clocked out. This allows the Laser to go back 10 times and re-read the data should there is error sensed by the DSP. Also, the VRDS-NEO is the ONLY transport currently available which is NOT suspended in any way. Still, even at this very high rotation speed, there is NO vibration you can sense. The READ error rate of the VRDS-NEO is almost 0 (if not 0) but Esoteric still uses the latest Digital Signal Processing with the most powerful error correction AND memory buffering in order to make sure that the error and jitter are indeed ZERO. There is no other disc spinning device (including CD/DVD-ROM) to offer these qualities.

Also, even though with computer based audio certain "error free" software can be used, this does not exactly mean that there are no transport device READ errors.

Any current $150 universal player uses powerful DSP and memory buffering which according to your and Lktanx theory is sufficient to do the job providing error and jitter free data output. Why don't you get one of these and hook it up to an external DAC together with your x1 reading and non-memory buffering VRDS Wadia and see which one will sound better? I can tell you right now; your Wadia will be a LOT better. Also, when you were talking about your friend’s computer based audio with external DAC did you try your Wadia as a digital transport through the same external DAC? If you have not, please do that and let us know if the computer based “error free” “transport” can provide the same bass extension and the same top octaves clarity, air, openness and resolution as your Wadia will.

In conclusion, it is a real fun for me to read all these "error free" discussions, but at the end of the day, there are many other VERY important things when it comes to digital audio other than "Zero" error.

Regards,
Alex

"Also, even though with computer based audio certain "error free" software can be used, this does not exactly mean that there are no transport device READ errors."

Alex, if one uses (and correctly sets up) Exact Audio Copy (EAC) along with a good CD-ROM drive that supports both C1 and C2 error correction (a Plextor Premium or similar) then you *will* get bit perfect copies, as long as there is nothing inherently wrong with the disk. If there is, EAC will give you an indication each and every time an error is detected. Any scenario which would cause a read error that was not detected by this set up (I'm not really sure that's possible) would neither be detected by a dedicated transport.

Having said all that, I agree with you completely that a bit perfect audio image is only part of the picture. But the tradeoffs between a server based bit perfect image and a fine transport are smaller than the D/A conversion of either of these signals, IMO. I've just recently moved to a server based world (a Squeezebox into my D/A converter), and guess what? That does not sound quite as good as my transport (a Proceed PDT3) into the same converter. Is it comparable to some of the other transports I've tried over the years? Yes. Is it scary close to what I have now? I'm afraid to say, yes, with the deficiency being (I believe) in the Squeezebox, and not in the server based delivery of a bit perfect signal.

---------------
Any current $150 universal player uses powerful DSP and memory buffering which according to your and Lktanx theory is sufficient to do the job providing error and jitter free data output. Why don't you get one of these and hook it up to an external DAC together with your x1 reading and non-memory buffering VRDS Wadia and see which one will sound better? I can tell you right now; your Wadia will be a LOT better. Also, when you were talking about your friend’s computer based audio with external DAC did you try your Wadia as a digital transport through the same external DAC? If you have not, please do that and let us know if the computer based “error free” “transport” can provide the same bass extension and the same top octaves clarity, air, openness and resolution as your Wadia will.
----------------------

Alex,

I am only discussing transports and their associated error correction circuitry. Let's not compare different issues. Of course a Wadia will sound different than a PC playing a CD. This difference is not and should not be due to the transport and error correction. This is because both the Wadia and the PC possess transports/error correction circuitry which produce ZERO errors.

The Wadia sounds different because it has a different clock reference with different jitter characteristics. The Wadia also has different digital filters and DAC. So obviously they should sound different. Nevertheless, I will not state which sounds better.

I am not claiming that all CD players sound alike. I am claiming that a properly designed CD player's sound should be completely uncorrelated with the transport. The sound will be a function of the following (not in any order of importance):

1. Digital filters
2. DAC
3. Clock reference
4. Clean analog power supply
5. Output driver stage of DAC

Note, the transport/error correction circuit is one thing engineers can do perfectly, inexpensively, repeatably, and in large quantities.

I am purely speculating on the actual numbers but here is an example:

High end transport = 1 error per minute
Cheapo transport = 100 errors per minute

Obviously the high end trasnport is better here. Now with error correction:

High end trasnport with EC = 0 errors per minute
Cheapo transport with EC = 0 errors per minute

I hope this helps you decide where to invest your hard earned $.

Tonyptony and Lktanx, every CD player, even the cheapest one, has C1 and C2 CIRC error correctors which have certain ability to "correct" the error. If the error exceeds the capacity of the C1 and C2 THEN you have an Error Flag output. So, if there is no error flag, this does not meant that there is no error; it means that C1 and C2 were able to correct the errors. Also, please be aware that there are also error correction errors which mean that C1 and C2 sometimes will "correct" something that did not need to be corrected. The other VERY important factor is the EFM Jitter, for example, if two different CD drives have the same error correction engines which will ALWAYS report Error free output, the one that has less EFM jitter will sound better.

In the case of my example in my previous post I meant not using the Wadia as a stand alone unit, but A-B testing it against the computer based "transport" through the same EXTERNAL DAC. In this case, digital filters, DACs and Analog stages will not be the cause of the difference.

My point was also that even a $150 universal digital player uses VERY powerful error correction and memory buffering using large 64Mb (and some times 128M and 256M) memory chips which completely "remove" error and jitter from the reader similar to what can be done with a computer based digital. So my question to you is why then those error and jitter "Free" digital players will not sound as good compared to even a 15 years old regular CD player when used as a digital TRANSPORT ONLY. I am not talking about stand alone use.

This is what I meant when I said that there are many other important things other than a fake "error free" digital data output.

Given the CD surface is really perfect, with the Esoteric VRDS-NEO transport the error is REALLY Zero, not only that, but the EFM signal jitter is also MUCH lower than anything else currently available.

I am sure that one day soon you will realize that “error free” and “bit perfect copy” doesn’t really mean anything when it comes to digital audio sound quality.

Regards,
Alex

Alex/Aplhifi,

Thanks for providing some corrections & more info on the VRDS-NEO transports. I also believe that NEO is used as a dual purpose: one, as in NEO = new & second, because TEAC uses NEOdymium magnets now.

IMHO, Lktanx posts, your posts & my posts are ALL in agreement - you are saying the same thing! I think that your posts have played remarkably well into our hands!

>> In conclusion, it is a real fun for me to read all
>> these "error free" discussions, but at the end of the
>> day, there are many other VERY important things when it
>> comes to digital audio other than "Zero" error.
Alex, this is exactly what we are saying! The transport is very important for reading the data off the CD, ensuring that the final result is actually or practically error-free. Once this is ensured, the sound of the CD/DVD player is determined by "many other VERY important things". It is hardly dependent on the CD transport at that point.

>> I am sure that one day soon you will realize
>> that “error free” and “bit perfect copy” doesn’t really
>> mean anything when it comes to digital audio sound
>> quality.
This is exactly what we are trying to emphasize as well, Alex!!
You are saying the same thing as we are, just using diff words.
Neither Lktanx nor I are belittling the importance of transports. However, what we are saying that they are means to an end (I wrote this in my orig post above). Once the final data is error-free (whether it is actually error-free when it gets read OR it is error-free after C1, C2 correction is IMMATERIAL to the DAC. I.E. the DAC does NOT care!) the sound of the re-produced music is dependent on "many other VERY important things when it comes to digital audio other than "Zero" error".

>> So my question to you is why then those error and
>> jitter "Free" digital players will not sound as good
>> compared to even a 15 years old regular CD player when
>> used as a digital TRANSPORT ONLY.
You know the answer to this, Alex! It is because there are "many other VERY important things when it comes to digital audio other than "Zero" error". It these other things (digital & analog power supplies, jitter, rise/fall edges, type of PCB material, DAC master clock, etc) that are severely lacking in these el-cheapo players 'cuz they are made to sell at a low selling price. It is not the 1/0 data read off by the cheap transport. If you want to blame the cheap transport then the blame should be levied on its cheap power supply that gets corrupted w/ the spiky read currents from the optical section & goes on to pollute ckts connected to this & other power supplies. IMO, this aspect belongs to the "other aspects" that you wrote about.

>> This is what I meant when I said that there are many
>> other important things other than a fake "error free"
>> digital data output.

>> Given the CD surface is really perfect, with the
>> Esoteric VRDS-NEO transport the error is REALLY Zero,
>> not only that, but the EFM signal jitter is also MUCH
>> lower than anything else currently available

whether it is "fake" or truely error-free, when the data gets to the DAC S&H, it DOES NOT matter & the DAC does not care. Error-free is error-free!
At this point the reproduced sound will depend more heavily on the DAC master clock jitter, analog & digital power supplies, linearity of the analog output stage(s), etc.
Also, in one of the above statements, you are addressing "jitter". Ah-uh, cannot do that, Alex! Jitter belongs to the "many other VERY important things" category you wrote about in your post!
What we are talking about here is the transport, the data read, the error correction(s) & the final data presented to the DAC.

>> Also, when you were talking about your friend’s
>> computer based audio with external DAC did you try your
>> Wadia as a digital transport through the same external
>> DAC?
I'm afraid that we did not! If I remember correctly we had a cable interface issue. At that time, we compared the Wadia integrated vs. his PC-based system.

>> Why don't you get one of these and hook it up to an
>> external DAC together with your x1 reading and non-
>> memory buffering VRDS Wadia and see which one will
>> sound better?
I am very close to doing this - I had to order a BNC to RCA adapter so that I could convert the output on the Wadia rear panel so that could use my digital cable. This will allow me to compare the Wadia transport against my stock Sony DVP-S7000. I'll keep you posted.

In the meanwhile I have been comparing my Wadia used as an integrated player w/ my stock Sony DVP-S7000 + Scott Nixon Saru DAC+.
Just like Tonyptony wrote: the Sony DVP-S7000 + Scott Nixon Saru DAC+ is SCARY close in sound to the Wadia integrated player. The cost of these 2 combinations is 32:1 with the Wadia being 32X more expensive! is my Wadia 32X better? Does it give 32X better bass & hi freq reproduced sound? NO SIR, IT DOES NOT! If the Wadia gave 1X better performance, it would 100% better, correct? I don't think that I could even say that! The Wadia is better, NO DOUBT, but marginally. The margin is significant enough that 1 listen will make it very apparent. If you listen to the DVP-S7000 + Saru DAC+ combination, there is hardly anyway that you could fault its performance. It is extremely musical. It is only when you pit it against a Wadia that the faults get highlighted. IMHO, the (little) David has given the Goliath a damn good run for its money. I wonder how close this "race" will get if I send my DVP-S7000 to Steve Nugent @ Empirical for mods? Hmmmm..... an $800 + shipping question.