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8 hours ago, Confused said:

Ultimately it goes back to needing a few more 'data points' before this makes more sense or at least we can discern some clear trends.

 

I would suggest these data points include the tx-USB Ultra into the chain. I had the opportunity to listen to the tx-USB Ultra together with the sMS-200 Ultra I already have in the chain this afternoon and this is another significant step forward in terms of transparency.

This tx-USB Ultra is, IMHO, a much more pertinent clue to our difference of perception than the cables. So better a Trifecta than an sMS-200 Ultra. Don't understand why, apart from charging more, they didn't package them together ;)

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1 hour ago, rickca said:

@julian.david is it not possible for Mutec to significantly improve the performance of the MC-3+ Smart Clock USB to yield something more cost effective than the REF 10 Masterclock?

 

Good idea ! Actually I had the same thought. Packaging the good LPSU of the Ref-10, a down-scaled Ref-10 with only one or two clock outputs, and one or two MC-3+ USB into one single box would be awesome. Would save some cable and allow for a 1st class reclocker all-in-one ;)

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4 minutes ago, SwissBear said:

 

I would suggest these data points include the tx-USB Ultra into the chain. I had the opportunity to listen to the tx-USB Ultra together with the sMS-200 Ultra I have already in the chain this afternoon and this is another significant step forward in terms of transparency.

This tx-USB Ultra is, IMHO, a much more pertinent clue to our difference of perception than the cables. So better a Trifecta than an sMS-200 Ultra. Don't understand why, apart from charging more, they didn't package them together ;)

 

Wow, the plot thickens! So your chain was: 

  • trifecta (modded switch+sMS-200ultra+tX-USBultra) > Mutec MC-3+ USB > Devialet DAC (using AES)?
  • Ref 10 feeding 10 MHz to sMS, tX, and MC-3+ USB?

As to why SOtM didn't package them together. Well ... the trifecta was not their brainchild. In fact, it was a discovery based on a conjecture (not even a theory) of @romaz's  - as he explained over on the other thread! His findings were soon confirmed by me and many others. Indeed, his first mods predated the existence of the Ultra gear - he essentially had them graft an sCLK-EX board into their existing DDC, the dX-USB HD. 

 

I don't think even SOtM expected the SQ benefits we derived! The Utra line came after those findings. After the fact - now - I do believe they offer bundles, at least through their US distributor Crux.

 

I am sure our findings here and on the other thread have not gone unnoticed by the Mutec's, the SOtM's, the Uptone's and the Sonore's, and others of the world. I am sure none of us want these absurd chains of devices, other than the result sounds so damn good!

 

In my mind, the race is on for a singular device that combines the goodness of the trifecta, DDCs like the MC-3+ and the SU-1, master reference clocks like the Ref 10, and PSUs like LPS-1 and the SR7. If I could get a single box at a fair price that did all that, while giving me the flexibility to attach an external PSU and reference clock, I would gladly replace my so-called "clock chain" with it.

 

It's a fantastic time to be a computer audiophile! :D

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2 hours ago, rickca said:

@julian.david is it not possible for Mutec to significantly improve the performance of the MC-3+ Smart Clock USB to yield something more cost effective than the REF 10 Masterclock?

 

I also hope to see something better at a price point somewhere in between the MC3+ and REF 10.

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I would be interested in a comparison between the REF10 and the Cybershaft 10MHz OCXO premium master clock.

 

$3k vs ~$800 usd

 

To be fair the Cybershaft only has one BNC output.

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On 9/11/2017 at 1:44 PM, barrows said:

The DS DAC from PS Audio always operates in master mode for its converter section, as it is an asynchronous DAC by design, that is it resamples all incoming data asynchronously to its single internal masterclock.  This does not matter what input you use.

 

Here is John Swenson's response to asynch USB DACs:

 

"But what about asynch USB, isn't the DAC in control? Overall yes, the DAC has its OWN FIFO and also checks it, but instead of changing a clock frequency it sends a command back to the computer which tells it to speed up or slow down the average sample rate. So even though the local DAC clock is in ultimate control of the sample rate, as far as the MC3+/USB is concerned the USB data stream is in control, it just passes it on down to the DAC."

 

 

 

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28 minutes ago, mourip said:

I would be interested in a comparison between the REF10 and the Cybershaft 10MHz OCXO premium master clock.

 

$3k vs ~$800 usd

 

To be fair the Cybershaft only has one BNC output.

 

Coincidentally, I just received a Cybershaft OP-14 in the house that is burning in. I will be trying it on my trifecta, and reporting on the novel thread.

 

I would love to do the comparison you suggested, but sadly, I don't live in the Utopian world of @SwissBear and @zoltan, where local dealers come by with loaner Ref 10s, and presumably, frankincense and myrrh.

 

This is 'Murica. That's not how we roll. 9_9

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12 minutes ago, romaz said:

 

Here is John Swenson's response to asynch USB DACs:

 

"But what about asynch USB, isn't the DAC in control? Overall yes, the DAC has its OWN FIFO and also checks it, but instead of changing a clock frequency it sends a command back to the computer which tells it to speed up or slow down the average sample rate. So even though the local DAC clock is in ultimate control of the sample rate, as far as the MC3+/USB is concerned the USB data stream is in control, it just passes it on down to the DAC."

 

 

 

 

Thanks Roy. I try to remind folks of this every chance I get.

 

Asynchronous USB only means the receiver controls the average sample rate. The data is still clocked by the source.

 

That is why reclockers/regenerators upstream can still impact the SQ of async USB.

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56 minutes ago, romaz said:

adding the reclocked modem/router/switch, ISO-Regen and tX-USBultra definitely improves things further.  

I suppose reclocking these components is only to improve streaming e.g Tidal or from a NAS.

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2 hours ago, romaz said:

 

Here is John Swenson's response to asynch USB DACs:

 

"But what about asynch USB, isn't the DAC in control? Overall yes, the DAC has its OWN FIFO and also checks it, but instead of changing a clock frequency it sends a command back to the computer which tells it to speed up or slow down the average sample rate. So even though the local DAC clock is in ultimate control of the sample rate, as far as the MC3+/USB is concerned the USB data stream is in control, it just passes it on down to the DAC."

 

 

 

RE the PS Audio DS, I was not referring to its USB input in this case, which is of course async as are all commonly used USB inputs.  I was actually referring to operation of the rest of the DAC after the USB input .  The I2S feed comes from wherever (any of the inputs) and is then oversampled into an entirely new clock domain controlled by a separate masterclock oscillator.  The masterclock in the Directstream is the only clock which has any involvement in what happens after that. 

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2 hours ago, austinpop said:

Asynchronous USB only means the receiver controls the average sample rate. The data is still clocked by the source.

This is factually inaccurate.  Asynchronous USB does the following:

 

Data stream coming in is buffered and the buffer is controlled by software, the software sends commands upstream to the serving device only to manage the buffer such that it does not get too full or too empty.  This is done so that there are always samples available to the output.

The output of the buffer is directly clocked by a free running oscillator, and the only thing which determines the timing of the samples is the accuracy of this oscillator: output jitter has no relation to anything going on further upstream (except perhaps due to low level noise effects affecting the local clocks jitter). 

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2 hours ago, austinpop said:

 

Thanks Roy. I try to remind folks of this every chance I get.

 

Asynchronous USB only means the receiver controls the average sample rate. The data is still clocked by the source.

 

That is why reclockers/regenerators upstream can still impact the SQ of async USB.

Thank you @austinpop for your valuable information.

 

This is the answer that I want for the question that I had asked about "why music playback by asynchronous USB process is still affected by accuracy of the clocks in the chain at upstream of the DAC" in several weeks ago.

 

At that time, instead of not getting this answer, I got a feeling in some of the subsequent discussion that people was always challenging the observations in this thread.

 

After all, I would like to point out that progress in many aspects (e.g. science & etc.) is made by questioning, making hypothesis, conducting experiments, observation, drawing conclusions and etc. By reiterating this process, human beings have achieved the advancement in these many aspects nowadays.

 

Thanks again to @austinpop for your valuable information.

 

Wish you a nice weekend. Cheers.

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5 minutes ago, simonklp said:

Thank you @austinpop for your valuable information.

 

This is the answer that I want for the question that I had asked about "why music playback by asynchronous USB process is still affected by accuracy of the clocks in the chain at upstream of the DAC" in several weeks ago.

 

At that time, instead of not getting this answer, I got a feeling in some of the subsequent discussion that people was always challenging the observations in this thread.

 

After all, I would like to point out that progress in many aspects (e.g. science & etc.) is made by questioning, making hypothesis, conducting experiments, observation, drawing conclusions and etc. By reiterating this process, human beings have achieved the advancement in these many aspects nowadays.

 

Thanks again to @austinpop for your valuable information.

 

Wish you a nice weekend. Cheers.

That information is inaccurate.  This is not how async USB works.  Just because something is the answer you "wanted" does not actually change how async USB receivers work.

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Just now, barrows said:

That information is inaccurate.  This is not how async USB works.

@barrows Ok. Fair enough. I welcome open minded discussion of counter theory.

 

Again, as I said that through questioning (or proposing counter theory), making hypothesis, conducting experiments, observation, drawing conclusions and etc, progress in the computer audiophile technologies and many other aspects can be made.

 

After all, we are in the 21st century now.

 

Wish you a great weekend. Cheers.

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2 minutes ago, simonklp said:

@barrows Ok. Fair enough. I welcome open minded discussion of counter theory.

 

Again, as I said that through questioning (or proposing counter theory), making hypothesis, conducting experiments, observation, drawing conclusions and etc, progress in the computer audiophile technologies and many other aspects can be made.

 

After all, we are in the 21st century now.

 

Wish you a great weekend. Cheers.

 

Just remember that a counter theory is only applicable to things that can be reasonably questioned. How isochronous USB protocol works is not one of those. A counter theory or a new hypothesis are not needed since there is a very clear and detailed documented definition. There is no doubt as to how it works, and @barrowsdescribed the function correctly.

 

Now, noise in the USB transmission and receiver is another matter and that is subject to (frequent) speculation and debates.

 

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42 minutes ago, pkane2001 said:

 

Just remember that a counter theory is only applicable to things that can be reasonably questioned. How isochronous USB protocol works is not one of those. A counter theory or a new hypothesis are not needed since there is a very clear and detailed documented definition. There is no doubt as to how it works, and @barrowsdescribed the function correctly.

 

Now, noise in the USB transmission and receiver is another matter and that is subject to (frequent) speculation and debates.

 

Ok, fair enough too. Also thank you for your valuable information.

 

I think even though your information is the fact, if other people have observations that appears to be in conflict with this, it is fine for any volunteer to propose new theory (not necessarily conflicting to the previous "fact") in an attempt to find out somethings that may be overlooked and/or etc., such as hypothesis in the area of "noise in the USB transmission and reception" that you have just mentioned.

 

The process mentioned by me earlier still applies except that it may start with observation and then questioning, making hypothesis, conducting experiments, … and etc., i.e. change in the process sequence only.

 

I think that this kind of situation had also happened in many aspects before, which includes the scientific or technological exploration fields.

 

Again, after all, we are in the 21st century. It is a nice to treasure the experience sharing and objective questioning from others.

 

Wish you a nice weekend too. Cheers.

Edited by simonklp

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38 minutes ago, simonklp said:

Ok, noted with thanks. Cheers.

The reason i am so adamant in my reponses is because it does a disservice to the community to suggest "theories" which are factually incorrect.

 

As I mentioned in my first response, the influence of noise coming over USB may be able to reduce clock performance in the USB receiver/DAC influencing jitter caused artifacts in the DACs analog output, hence the great lengths we go to with Sonore Rendu products to reduce that noise.  I have no doubt that USB source qualities can influence the overall outcome of system performance, but the important point here is that the clocking of Async USB is not reliant on the upstream clocks, the only clocks which matter (for this) are those which clock out the I2S feed from the USB interface buffer.

The upstream clock(s) appear to exert what I would term a second order effect which may effect DAC output quality, but the important distinction is that this effect is not directly related to how the I2S data is clocked out of the USB interface.  This is why Sonore uses a "femto" clock in the ultra and Signature Rendu products.  The only plausible explanation for this second order effect is noise coming over the USB input, causing some disruption in the DAC (ground bounce, etc).  

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45 minutes ago, barrows said:

The reason i am so adamant in my reposes is because it does a disservice to the community to suggest "theories" which are factually incorrect.

 

As I mentioned in my first response, the influence of noise coming over USB may be able to reduce clock performance in the USB receiver/DAC influencing jitter caused artifacts in the DACs analog output, hence the great lengths we go to with Sonore Rendu products to reduce that noise.  I have no doubt that USB source qualities can influence the overall outcome of system performance, but the important point here is that the clocking of Async USB is not reliant on the upstream clocks, the only clocks which matter (for this) are those which clock out the I2S feed from the USB interface buffer.

The upstream clock(s) appear to exert what I would term a second order effect which may effect DAC output quality, but the important distinction is that this effect is not directly related to how the I2S data is clocked out of the USB interface.  This is why Sonore uses a "femto" clock in the ultra and Signature Rendu products.  The only plausible explanation for this second order effect is noise coming over the USB input, causing some disruption in the DAC (ground bounce, etc).  

 

@barrows Thank you very much for your valuable information.

 

This is what I treasure to have discussion or sharing accompanied with so much new information to me.

 

There are always new things for me to learn in the CAS technology. That's the reason I always browses through this forum to understand more.

 

So, do you mean that the plausible explanation to the effect of upstream clocks is due to their lower noise instead of their higher timing accuracy? Am I understand it correctly?

 

Thank you again for your valuable information. Cheers.

 

Edited by simonklp

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9 minutes ago, simonklp said:

So, do you mean that the plausible explanation to the effect of upstream clocks is due to their lower noise instead of their lower timing accuracy? Am I understand it correctly?

The only plausible explanation is that the result of a better clock in the upstream digital USB source (say an ultra Rendu) is that the improved timing reduces noise on the USB feed to the DAC.  I will not rule out the possibility that there might be some other advantage to a better clock in this position, but at this time it appears to be extremely unlikely, to the point of being virtually absurd.  Note the same does not apply to digital sources where one is using a SPDIF output, that is an entirely different thing, I am referring to USB output devices here.

As this is the mutec clock thread, i would also suggest that it is crazy to use such a high quality clock on (like an SMS-200 ultra) a USB output device unless first the actual DAC clock has been brought up to at least the same low level of phase noise.  Upgrading the DAC clock is going to offer an exponentially better improvement than upgrading the clock in a USB source device ( or router, switch etc).  For the price of the Mutec, one could get a competent tech/modder to put a really awesome clock(s) upgrade in their DAC for a much larger performance increase.

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2 minutes ago, barrows said:

The only plausible explanation is that the result of a better clock in the upstream digital USB source (say an ultra Rendu) is that the improved timing reduces noise on the USB feed to the DAC.  I will not rule out the possibility that there might be some other advantage to a better clock in this position, but at this time it appears to be extremely unlikely, to the point of being virtually absurd.  Note the same does not apply to digital sources where one is using a SPDIF output, that is an entirely different thing, I am referring to USB output devices here.

As this is the mutec clock thread, i would also suggest that it is crazy to use such a high quality clock on (like an SMS-200 ultra) a USB output device unless first the actual DAC clock has been brought up to at least the same low level of phase noise.  Upgrading the DAC clock is going to offer an exponentially better improvement than upgrading the clock in a USB source device ( or router, switch etc).  For the price of the Mutec, one could get a competent tech/modder to put a really awesome clock(s) upgrade in their DAC for a much larger performance increase.

 

@barrowsThank you again for your valuable advice. In fact, this is actually the discussion or information that I would like to get.

 

I had made an incorrect statement in my earlier message in this thread about 2 hours ago. In fact, my question about "why music playback by asynchronous USB process is still affected by accuracy of the clocks in the chain at upstream of the DAC" in several weeks ago was made in another thread namely "A novel way to massively improve the SQ …". At that time, I stated statements in that thread, which is listed as follows: -

QUOTED

"I had doubt that whether this kind of improvement by using a better clock (e.g. sCLK-EX) only applies to cases where the Asynchronous USB Transfer mode is not properly implemented. Because under this transfer mode, the clock of the DAC is the master that the clocks of the upstream devices should not really affect so much.

 

For example, in case of playback using HQPlayer with NAA, the NAA isolates as much as possible at the software side by using a large asynchronous FIFO buffer. Is there really a substantial improvement by replacing the original clocks by better ones at the upstream side of DAC? Was there any experiment on this case? Thank you for your kind advice in advance."

UNQUOTED

 

At that time, neither did I get related advice nor the related information. Instead, there was comment in the thread criticising people of their act to question the observation of others. It was not a good experience to me. That's the reason why I always say that I always treasure contradicting information, questioning, sharing experience and information and etc. so that progress maybe made.

 

In any case, it's good to communicate with you and learn more from you.

 

Thank you again for your kind advice and sharing. Cheers.

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4 hours ago, romaz said:

 No matter how good a DAC, no matter how many defenses it implements to ward off RF and jitter, it would appear to me that there are huge gains to be had by paying attention to your digital front end.

 

Roy,

 

Thanks for another invaluable post.

 

Your sentence above perfectly represents my experience too. 

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