Mutec REF 10 Masterclock

[romaz]

On 5/18/2017 at 1:26 PM, julian.david said:

The REF 10 is arguable the most compatible 10 MHz clock out there and it will work in conjunction with various 10 MHz compatible DACs and clocks by manufacturers - not just MUTEC. It is however a strict 10 MHz clock, so you will need a 10 MHz reference input of some sort. The dCs Vivaldi Master Clock has a 10 MHz compatible reference input and the REF 10 will be an excellent choice to drive this input. But the other Vivaldi products (Upsampler, DAC) only have Word Clock inputs and (unfortunately) don't provide a 10 MHz input. So you would need some other master clock in between (like the dCs or the MUTEC MC-3+/MC-3+USB) to generate and distribute the Word Clock signal to the upsampled or DAC. 

 

Unfortunately dCs doesn't publish any phase noise figures for the Vivaldi Master Clock, which is the figure to pay attention to. But to my knowledge, the phase noise performance of the REF 10 is unmatched at the moment!

 

Had a great time with the new REF 10 today.  Thank you, Julian (and Christian)!

 

Unbelievable noise floor measurements from 10Hz to 10kHz but ultimately, the proof is in the listening.  Even amidst the noise of the MOC in Munich and the fact that the REF 10 was connected to the MC-3+USB which was then connected to a modest headphone setup via a high jitter Toslink optical cable, the impact of this clock over the MC-3+USB's standard clock was amazingly obvious from the standpoint of increased air around voices and instruments and size of the sound stage but also a much smoother presentation.  In comparison, the MC-3+USB's stock clock was almost unlistenable.  Quite surprised by this delta and much much larger than the delta I heard with the Vivaldi and the Vivaldi Master clock.  Steep price and despite my initial skepticism based on experience with other master clocks, I found myself already reaching for my wallet for what I now consider a must have.  Perhaps, the surprise of the show for me and I will probably use this to synchronize 3 SOtM sCLK-EX clock boards.  Amazing performance as well as versatility!

[romaz]

2 minutes ago, Confused said:

I'm kind of thinking aloud today, but to put my last post a different way, if I could get somewhere close to the performance of the dCS Vivaldi Upsampler + Clock (£24k in the UK), with something like a PC with HQPlayer, sMS-200Ultra, Mutec MC3+USB & Ref 10 Clock, then I would be very happy indeed, and I do actually suspect this is possible.  But is there a better way?

 

I would suggest you get the sMS-200ultra with the master clock option so that you can extend the benefits of the REF 10 to that device as well.  To be able to synchronize that device with the Mutec should result in a very nice further improvement.

[romaz]

Just now, Confused said:

Thanks romaz, that does look like a very interesting option.  I have been following the 'A novel way....' thread with great interest, so I get the point, however I had not yet worked out the possibility of feeding the sMS-200Ultra with a Ref 10.  That's quite a compelling idea, I wonder!   And even if it did not work out for reasons as yet unknown, you would still have a Ref 10 fed Mutec to keep you happy.

 

It will absolutely work with the sMS-200ultra.  I have already verified this with SOtM.  To be able to synchronize the clocks on both the Ultra and the MC3+USB will be huge.

[romaz]

26 minutes ago, jelt2359 said:

To use this with the SMS200Ultra, would you need to feed it with a signal from the Mutec 3+ USB? Or can you go direct Ref10 -> SMS200 Ultra?

 

Each device requires its own 10 MHz input from the REF 10. Fortunately, the REF 10 has 8 outputs.

[romaz]

19 minutes ago, Confused said:

Thinking about this, why do you need the sMS-200Ultra, which from what I understand is basically a sMS-200 with better clock?  If the original sMS-200 can be modified to accept an external clock, is this not the best 'bang for your buck' solution?

 

The standard sMS-200 is incapable of a master clock input. The new sCLK-EX board in the sMS-200ultra, however, is capable of such an input although the option to fit it with the necessary BNC connector will cost an additional $200.

[romaz]

6 hours ago, BigAlMc said:

No answer for 2 days - doh! - does that mean I asked a doozy of a dumb question??

 

Not a dumb question.

 

Your SU-1 has no master clock input option nor does its clock operate at 10MHz and so there is no direct way to associate the REF10 with the SU-1 although there is an indirect way.

 

This is where SOtM's revolutionary new sCLK-EX board comes in but there's a catch.  This new clock board has the option of a 10MHz master clock input (50 or 75ohm) and further has 4 independent (but synchronized) outputs that can be used to replace the clock of almost any component (i.e. router, switch, motherboard, LAN card, video card, USB card, etc).  I know this as I have done it already and the results have been spectacularly good, so good that I have purchased a 2nd sCLK-EX board and will be replacing 4 more clocks in my chain (a total of 8 clocks) from the router all the way to my final endpoint.  What this means is that I will have every clock in my audio path replaced and the REF10 will be used to synchronize all 8 clocks.  Moreover, since the REF10 will be powered by its well thought out linear PSU and since each of SOtM's clock boards (and its 4 clocks) can be powered by a high quality linear PSU (in my case, my Paul Hynes SR7), regardless of the dirty environment that each clock is placed into (ie a music server), each clock will be powered very cleanly.  What kind of improvement this leads to, I'm not yet sure, but thus far, the results with 4 clocks replaced have been breathtakingly good.  

 

In theory, the sCLK-EX can be used to replace the clock on the SU-1 and I'm willing to bet, based on my own experience so far and based on the comments made by others, that there will be an improvement even without the REF10 but the improvement will be even larger with the REF10.  The only problem is SOtM has suggested they will not replace clocks on products made by other audio companies.  Whether there are exceptions to the rule, I'm not sure.

 

If you are interested in my further impressions of the REF10, they are posted here:

 

 

[romaz]

4 hours ago, 4est said:

Forgive my ignorance please, but how are these clocks synchronized? I do not understand how say a master clock at 24.567MHz gets sync'd to USB at 12MHz(or whatever it is).

 

I am not a clock expert and so I have no choice but to accept statements made to me by clock designers and manufacturers at face value but according to Lee, SOtM's lead engineer and the gentleman responsible for the sCLK-EX clock board, the 4 clock outputs on this board are capable of independent frequencies but ultimately, the precision of their timing is "synchronized" to the performance characteristics of a single internal oscillator, an "internal master clock", if you will.  A similar analogy would be a computer motherboard's system clock operating at 24.567MHz but providing timing to various buses on the motherboard via DPLL even though those buses operate at frequencies other than 24.567MHz.  There is a language barrier when speaking with Lee since English is not his native language but he used the word "synchronized" repeatedly as the reason for why his clock board sounds so good and the primary reason why any audiophile should consider an external master clock.  Regardless of the exact technicalities involved, what matters more to me is the resultant improvement in SQ.

 

Isolating the impact of a clock in a component isn't always easy but with SOtM's standard endpoints, such as the sMS-200, tX-USBhubEX, or dX-USB HD and their corresponding "Ultra" versions, the only difference is the clock and so it becomes easy to appreciate the difference their new clock makes and the difference is surprisingly large with respect to increased air around voices and instruments resulting in a more 3D presentation but also resulting in the better layering of detail and discernment of subtle nuances that are easily and consistently differentiated with blind testing.  Even when their new clock was applied to an inexpensive $20 network switch, the improvement was shocking and when 4 Ultra endpoints were combined in series, all I could do was shake my head in disbelief with how my music had taken on new life while sounding smoother and more grain-free.  This wasn't any form of artificial romantic coloration that I could detect, it was simply realism taken to another level.

 

Now, when I got a chance to first listen to the REF10 in Munich, I was aware of all the criticism against external master clocks by the nay-saying experts and how the long clock cables involved would surely degrade the signal and based on my mediocre experience with the dCS Vivaldi master clock last year, I was admittedly skeptical but the REF10 has completely changed my mind about how impactful a well implemented external master clock can be.  In the same way that SOtM's sCLK-EX transformed their standard endpoints, the REF10 did the same with their MC-3+USB but perhaps to an even greater degree.   I hope to receive my REF10 and a pair of Habst clock cables in a few short weeks and so I will get a chance to hear for myself its impact in my system.  I will report my findings at that time.

[romaz]

My REF10 and Habst clock cables have arrived.

 

The REF10 is connected to 2 SOtM sCLK-EX clock boards.  These boards have been used to replace the clocks on a small mini-ITX SoC motherboard, incoming LAN adapter, outgoing SOtM tX-USBhubIN USB card and tX-USBultra.  The tX-USBultra then connects directly to my Chord DAVE and so this is a straight USB setup.  In the next couple of weeks, I will also have my internet modem/router/switch reclocked and so eventually, 8 clocks will all be synchronized to the REF10 and I will have no bad clocks in my direct path.  It should be clear by now just how revolutionary SOtM's sCLK-EX board is.  Everything is being powered by independent rails from several Paul Hynes SR7s including my SOtM clock boards.

 

Upon first listen, I heard no difference.  Nada.  It sounded very good but with the REF10 activated or deactivated, I heard no change.  I have to admit I was a little worried.

 

I let things run continuously overnight and oh my, how things have opened up.  I'm sure more break-in is required and sound quality will improve further and so I will wait another couple of weeks before commenting further but what I am hearing already is just breathtakingly good.  The dimensionality and atmosphere of my live recordings are now at a level I have never ever heard before in my system and I have had many servers come through my system including an Aurender W20, CAD CAT, Lumin U1, Baetis Reference (original), Melco N1ZH  and Antipodes DX (2nd gen), just to name a few.  This list doesn't include the dozen or so servers I've built myself, a RedNet 3, and just about every USB and Ethernet gadget you can think of.  The layering of detail in my orchestral tracks is just crazy good and perceptible at even whisper levels.  Bass definition and dynamics, midrange texture and clarity, treble extension and air, yes, it's all there.  People talk about great clocks making the biggest difference in the bass and lower midrange but I must say, I hear it's impact everywhere.  Perhaps what stands out the most is how smooth and grain-free the sound is.  I thought my system was already free of harshness but this level of smoothness is a whole other level.  I've been listening for the last few hours and no fatigue, just amazement at how my music has taken on new life. 

 

Before this, I had a quad Ultra stack at my disposal (SOtM sMS-200ultra with Ultra reclocking switch, tX-USBultra and dX-USB HD Ultra.  More recently, I added the Iso Regen and so my system is not a stranger to well-clocked components.  As you would imagine, my system already sounded very very good and it was unfathomable that my previous setup could be beat so easily and yet, somehow, with this simpler setup + the REF10, I have beat it...and not by a small margin.

 

I'm off for a much needed holiday and so I won't be reporting back for a couple of weeks nor will I be offering a response to this post anytime soon.  By then, hopefully, my setup will be complete (which will include a reclocked router and a few other surprises).  What I will say is don't let anyone tell you an external master clock can't make a huge difference.  They have no idea.  

[romaz]

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."

 

 

 

[romaz]

I'm back from my travels for now.  I also just a few days ago received my gear back from SOtM.  I have gone a bit crazy with my build, more than I really needed to but I wanted to answer for myself certain questions about what matters and what doesn't with respect to all this clocking.  While I will need more time to draw my definitive conclusions, here is what I can say for now.

 

Back in Munich, I was quite enamored with how the REF10 elevated the SQ of Mutec's very fine MC-3+USB, enough so that I bought the REF10.  While I fully believed the REF10 would elevate SOtM's products, I didn't know to what extent and so this was a bit of a gamble.  I would have to agree with SwissBear that the REF10's impact on individual Ultra components from SOtM is less prominent when compared against what I heard with the MC-3+USB.  Is this because the sCLK-EX's stock internal clock is better than the stock clock in the MC-3+USB?  I'm not sure but if someone is going to buy a REF10 for something like the sMS-200ultra and stop there, I'm not sure I would consider a REF10 purchase worthwhile.

 

Where the REF10 earns its keep (and boy, does it earn it) is when its abilities are applied en masse.  From one component to the next, I have noticed a variable impact but as you add them together, it becomes an "OMG" moment.  As of now, here are the 8 clocks I have replaced using 2 SOtM's sCLK-EX clock boards:

 

1.  Netgear C3000 cable modem/router/switch - 2 clocks.  There are more powerful devices like this out there with a richer feature set but I specifically chose this model because it uses low power components.  While this device has Wi-FI capability, I don't use it.  I use a separate device in a separate room as my Wi-Fi access point for my home and so this device only serves as an internet modem, simple router and 2-port switch.  It only draws 1.5A at 12V and so it was my feeling that this would result in better SQ.  When I compared it against my much more powerful Netgear Nighthawk Wi-Fi router which draws up to 3.5A, with each powered by their stock SMPS, I found slightly better SQ with this low power C3000.  Powering either with a 12V lead from my Paul Hynes SR7 predictably improved SQ but again, I felt SQ was slightly better from the low power C3000.  As such, I sent this unit to SOtM and they replaced its 2 clocks and added capacitors.  The switching regulators could not be replaced due to excessive heat concerns.

 

2.  DFI BW171 motherboard - 1 clock.  This is a mini-ITX motherboard with an embedded Celeron that consumes no more than 8 watts.  It is passively cooled, has a very small electrical footprint and when powered by my SR7, SQ was superior to my modified Mac Mini which was also powered by my SR7.  This board's 25MHz system clock was replaced.  This system clock then serves as a reference clock for many "subclocks" embedded within the motherboard and many of these clocks are not replaceable but there are ways around this.  For example, the USB clock on this motherboard can't be replaced although if you use a PCIe USB card, the clock on that card can be replaced.

 

3.  Intel i211AT 2-port LAN board - 1 clock.  Because of lack of available PCIe slots, I chose to use the motheboard's integrated LAN board.  Each of the 2 ports has its own clock that is replaceable but because these clocks are identical, I was able to use a single clock from the sCLK-EX board to provide clocking to both ports.  If I was outputting to an Ethernet endpoint such as an sMS-200ultra or ultraRendu, I probably would have opted for a dedicated PCIe Ethernet card where capacitors can be added and the switching regulators replaced.

 

4.  SOtM tX-USBhubIN - 1 clock.  This internal USB clock board is the same board used in the tX-USBultra.  Many will be surprised to know that I chose this card not as an output card but as an input card.  Many who have followed my build on the other thread know that I noted a nice bump in SQ when I connected my music data drive to an Adnaco fiber USB card instead of one of the motherboard's stock USB ports.  With further testing, I found a further bump in SQ with this card over the Adnaco and so this card is used to connect my array of Lexar 512GB compact flash cards for music storage (presently 2TB worth of storage).  I have found this solution easily superior to anything I have tried thus far, either direct storage or NAS.

 

5.  SOtM tX-USBexp USB card - 1 clock.  This is SOtM's PCIe-based USB card.  If I had another available PCIe slot, I would have bought 2 of these instead of the tX-USBhubIN card because according to Lee, SOtM's lead engineer, this card is his finest product.  Of interest, while at Munich, he described his sMS-200ultra and tX-USBultra as his "mid-level" products.  He suggested his very best product is his sMS-1000SQ and a large reason for this is because of this card.  While similar in many ways, the USB chipset, regulator circuitry and the filtration built into this card are his very best.  He said with this card in "Ultra" form, there should be no need for an sMS-200ultra.  As an owner of an sMS-200ultra, I would have to agree.

 

6.  ISO-Regen - 1 clock.  I have to agree with SwissBear, this very fine device is a step down compared to the tX-USBultra with regards to resolution and while I like how it improved the tonal density of my slightly thin SOtM setup, the perceived compromise in resolution made it a "no-go" for me -- unless of course I could replace its clock and so that is what I have done.  First off, SOtM will not replace the clock on any ISO-Regens.  While they have great respect for Uptone Audio, they feel this device is too close a competitor.  Feel free to ask them but don't be surprised if they politely tell you "no."  With that said, there are many out there with the skill set to replace the 25MHz clock on the ISO-Regen for those so inclined.  Is this modified ISO-Regen now at the level of the tX-USBultra?  Not quite.  I still prefer the tX-USBultra as my final endpoint before my DAC but the improvement is undeniable.

 

7.  tX-USBultra - 1 clock.  This unit served as the host for my 2nd sCLK-EX board and is the endpoint that connects directly to my DAC.  

 

What the above setup allows me is that from the beginning of my digital chain up to my Chord Blu Mk2 / DAVE, every bad clock that I can replace has now been replaced to the level of the REF10's OCXO.  With the exception of my OS drive and my compact flash USB hubs that I use for storage, everything is powered by independent rails from several Paul Hynes SR7s.  What I am saying is that both clocking and power delivery are of an equivalent standard from beginning to end.

 

Now, Chord DAVE is an asynchronous USB DAC and in fact, this is its best input.  Rob Watts implemented a floating USB design that provides very effective galvanic isolation to the extent that an Intona made no positive difference.  Even the galvanic isolation offered by the ISO Regen results in minimal impact.  Chord's new Blu Mk 2 with built-in M-scaler has now been added to my chain and what this effectively does is it increases DAVE's TAP resolution 6-fold to the extent where DAVE now has a TAP-length filter in excess of 1-million TAPS.  This device also incorporates galvanic isolation and paired with DAVE, it was assumed by many including Rob Watts that all of my tinkering would have much less impact, if any at all.

 

Despite the gigantic impact of the M-scaler in Blu Mk 2 to my Chord DAVE, my server build with all clocks replaced seems to be making an even larger impact than before.  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.  While the REF10s impact on any individual component ranges from small to large, its collective impact on my whole chain cannot be adequately expressed in words because as of now, I have never heard a system quite like this with respect to smoothness, resolution, transparency and dynamics.  These are traits generally reserved for analog devices like amplifiers and speakers and so to make this claim with digital gear before the DAC is really quite a statement.

 

Like many of you, I value simplicity whenever I can get it which is one of the reasons I went away from Ethernet endpoints like the sMS-200ultra.  As a minimum, I know I could be very happy using a single sCLK-EX board (and its 4 clocks) and forgo reclocking the modem/router/switch, Iso-Regen and tX-USBultra.  This means that with a single box server with integrated sCLK-EX board, a 4-rail SR7, and a REF10, I would feel I was in end-game territory but I will say that adding the reclocked modem/router/switch, ISO-Regen and tX-USBultra definitely improves things further.  

 

Lastly, with regards to clock cables, I have explored this to some extent although I have a few other clock cables coming in.  With the Habst cables against a 0.5m Pasternack RG-59 (about $40) and a 0.5m Blue Jeans Cables RG-6 with Canare BNCs ($17), there's no contest, unfortunately.  With these lesser cables, there is an obvious HF glare that is present.  I can get used to it and things can sound pretty good but as soon as I swap in the Habst, the improvement in detail clarity and the disappearance of this glare is very apparent.  If someone is contemplating an inexpensive clock cable, I would suggest the less expensive Blue Jeans Cables over the Pasternack.  Whether this is because RG-6 is better shielded and has less signal attenuation then RG-59, it's hard to say but one seems to sound a little better than the other although the difference is small.  Next week, I have a Black Cat Silver Star 75 coming in.  It is supposed to play in the league of the big boys at a more affordable price point of $250 and so we'll see.

[romaz]

3 hours ago, barrows said:

I would also stress that unless you have a system such as @romaz, it is also a bit daft to suggest that "huge gains" will be made with adding a $3K clock to a USB output device.  

 

It seems that my statement has been misrepresented.  I will quote what I actually stated and I stand by it:

 

"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."

 

Notice that I made no mention of a $3k clock.  If my above statement were not true, then there would be no justification in buying a Sonore Signature Rendu SE (also selling for $3k) -- we should just pour this money into a better DAC.  But to borrow your own phrase, Barrows, "everything matters," and my findings with better power supplies, better clocking, etc. with respect to these upstream digital components are just as applicable to my $600 Chord Mojo and $1,300 Oppo BDP-205 as they are to my Chord DAVE.

 

Regarding what a good clock does in these upstream components, I agree with you.  It's about noise and not timing.  Here is John Swenson's quote:

 

"As discussed in this thread a high frequency clock can have at least three different "uses".

1) integer multiple of a word clock, DACs frequently have two of these, one for each of the sample rate families.

2) clock used for "processing" not related directly to sample frequencies

3) reference for a frequency synthesizer (which may be producing #2 frequencies)

 

Very few DACs actually use word clocks any more. Most of them use some form of #2 clock.

 

The Ref10 is designed to be a #3 source. For most audio equipment it cannot be used directly since not very many boxes have frequency synthesizers built in.

 

#2 are clocks that are fed into things like processors, USB receivers, PCIe boards etc. They are not related to audio sample rate frequencies at all, but observations seem to indicated that they can effect ultimate sound quality. The mechanisms for this are not known. I do have a theory I have been working on that explains this but it is very preliminary at this point and I'm not willing to make it public yet."

 

It's ok if people are skeptical of the impact or the value of clocking in these small "spaghetti" devices.  For sure, it shouldn't be anyone's first priority but just to be clear, when I report findings, that's all I'm doing.  I have no agenda to promote as I am not trying to sell anything to anyone.  I have paid for everything I have and I have no financial relationship with any audio company.  

 

Here is an interesting quote from John Swenson regarding the ultraRendu:

 

"2) much lower jitter clock.

When the microRendu project was started really good clocks were large and expensive so the choice was made to go with with a good but not best available clock. At this point we didn't understand how critical this next step in lower noise clocks was for many USB input DACs.

 

But now VERY low noise clocks are much smaller and less expensive than they were (still not cheap, but significantly less than before) so it was decided it was very important to use these in this design. This is probably the most important improvement over the microRendu."

 

It seems that with the ultraRendu, the clock does matter.  All that the REF10 seeks to accomplish is to improve this clock even further.

 

Regarding the value of a $3k+ external master reference clock like the REF10, value is always relative.  As Julian so wisely said, compared to how expensive some external master clocks can get, before having heard it, I found the REF10's asking price to be fair.  Considering the REF10 gives you 8 galvanically isolated clock outputs with a choice of 2 different impedances, considering its well implemented linear PSU, considering the very high build quality, but most importantly, considering its stellar performance, I consider the REF10 to be an outright bargain.  As I consider the quality of my current music server build and as I compare it to things I have heard in the past including such things as a $17k Aurender W20 or my former $9k CAD CAT, this current build easily supersedes those servers and I attribute this to 3 trump cards:  (1) my power supply, (2) the sCLK-EX boards that allow me to reclock almost any device, and (3) the REF10.

 

[romaz]

24 minutes ago, barrows said:

@romaz  Exactly, but i think you are missing the point I was trying to make:

 

For someone like you with a Digital front end >$20K (blu+DAVE) improvements in your D/A converter are going to be hard to come by, perhaps impossible, so going all out with experiments on source feeding that combo may be justified as your last area to achieve gains in sound quality.  But what has happened over in the other thread (and some here, as they seem to have been linked) is that readers are getting the idea they are going to get "big gains" by doing this.  I am only trying to bring back some sense of scale and relative importance to the discussion.  For example: spending thousands of dollars on re-clocking a router or switch, or a Regen type device is going to be wasted money when much bigger gains could be had to the audiophile who is using a lower level DAC.  People with more moderate DACslike an Ayre Codex or Mytek Brooklyn would eb better served by first putting that money into a better DAC first (even more so better speakers if they do not already have Vivid Audio Giyas or something similar).

Maybe my perceptions of the value of "upstream tweaks" is somewhat ameliorated by the USB source I use, but I am not going there fully as this is not a Sonore thread.  I do value some upstream tweaks in my own system, like the custom built ultra low noise power supply I built for my router, which we will be using at RMAF, but if you read this thread there are some folks here who fully do not understand even what kind of influence upstream clocks can have (noise as you and I agree, and not better data timing in the direct sense). 

 

In addition my posts are not meant to be any criticism of the Mutec components, for their intended purpose I expect they are excellent, and the clock itself, if it actually meets the claimed specs is excellent for its intended purposes (clock distribution necessary in Pro audio environments), and I agree the price appears to be quite fair as well for a non asian origin product.

 

Barrows, first of all, much respect to you and Sonore.  I am well aware of the great things you are capable of and having met you, Adrian, and Andrew at RMAF last year, and as a proud owner of a microRendu, know that I hold Sonore in high regard.  Having partnered with John Swenson, you guys have some serious IQ over at Sonore and it shows.  Contrary to how things might be perceived, if I have a bias, as an American, it is to see a small American company like Sonore succeed and succeeding, you guys are.

 

Having said that, if my effusive praise of the REF10 seems disproportionate to your perceived value of it relative to other devices in a digital chain, I want to remind you that I am posting in the REF10 thread.  If there is a place to be able to speak openly and candidly about the REF10, this is that place.  Having clearly stated what DAC I use, people can make up their own mind about how it might translate in their own system.  I would like to think that anyone reading this thread who can afford a REF10 and might be interested in a REF10 isn't going to be a fledgling audiophile and isn't going to use it to reclock their iPhone.  Absolutely, the REF10 is not the first component anyone should buy but nonetheless, this is one remarkable piece of kit.  There are many who jump onto this thread and make comments of what's possible or not possible based on theoretical grounds and have never actually heard the REF10.  The perspective that I offer is that of an actual REF10 user.

 

While it appears Sonore has not yet substantiated the impact of clocking in these "spaghetti" devices, I would encourage you guys to give it a go.  Where there's smoke, there's usually fire, and so I believe you will find that the many who have gone down this path are not just listening to placebo.

[romaz]

11 minutes ago, barrows said:

This is a exactly what John S. is doing.  Hopefully his research will be able to determine the mechanism for any improvements, and then audiophiles can move forward in an informed way.  Of course we are well aware of the value of a better clock in our Ethernet Renderers, we first started experimenting with that long ago, which led to the development (among other things) of the ultraRendu and Signature Rendu SE.

But, if I am going to use clocks as accurate as the Mutec claims to be, they are going in my DAC first as a replacement for the audio clock(s) where they can do the most good.  Of course audio clock frequencies will not have as low phase at low frequencies as a 10 MHz clock can (phase noise scales with clock frequency all other things remaining equal) but using a fixed frequency clock at audio frequency will perform better than a 10 MHz reference clock used to generate (digitally) audio frequency clocks.  There are now some pretty nice audio frequency clocks available at semi-reasonable prices.

 

This is what is so challenging with digital audio.  No one truly understands it all.  What I respect about people like John Swenson and Rob Watts is that they fully acknowledge this and that some phenomena are inexplicable but just because certain observations are inexplicable, does't make them invalid.  Look how routinely Sonore and Uptone Audio get bashed on ASR based on lack of measurements.  It seems some people, purely based on theories or measurements, already know how somethings sounds even before the needle hits the groove.

 

With regards to the clock in a DAC, this appears to be a very complex topic and more than I am willing to tackle with my DAVE.  Here is what Rob Watts has to say:

 

"The issue of clocks is actually very complex, way more of a problem then in simply installing femto clocks. People always want a simple answer to problems even if the problem is multi-dimensional and complex. I will give you a some examples of the complexities of this issue.

 

Some years back a femto clock became available, and I was very excited about using it as it had a third of the cycle to cycle jitter of the crystal oscillators we were using. So I plugged it in, and listened to it. Unexpectedly, it sounded brighter and harder - completely the opposite of all the times I have listened to lower jitter. When you lower jitter levels in the master clock, it sounds smoother and warmer and more natural.

 

So I did some careful measurements, and I could see some problems.

 

The noise floor was OK, the same as before, and all the usual measurements were the same. But you could see more fringing on the fundamental, and this was quite apparent. Now when you do a FFT of say a 1 kHz sine wave, in an ideal world you would see the tone at 1 kHz and each frequency bucket away the output would be the systems noise floor. That is, you get a sharp single line representing the tone. But with a real FFT, you get smearing of the tone, and this is due to the windowing function employed by the FFT and jitter problems within the ADC, so instead of a single line you get a number of lines with the edges tailing of into the noise. This is known as side lobes or fringing. Now one normally calibrates the FFT and the instrument so you know what the ideal should be. Now with a DAC that has low frequency jitter, you get more fringing. Now I have spent many years on jitter and eliminating the effects of it on sound quality, and I know that fringing is highly audible, as I have done many listening tests on it. What is curious, is that it sounds exactly like noise floor modulation - so reduce fringing is the same as reducing noise floor modulation - they both subjectively sound smoother and darker with less edge and hardness.

 

So a clock that had lower cycle to cycle jitter actually had much worse low frequency jitter, and it was the low frequency jitter that was causing the problem and this had serious sound quality consequences. So a simple headline statement of low jitter is meaningless. But actually the problem is very much more complex than this.

 

What is poorly understood is that DAC architectures can tolerate vastly different levels of master clock jitter, and this is way more important than the headline oscillator jitter number. I will give you a few examples:

 

1. DAC structure makes a big difference. I had a silicon chip design I was working on some years back. When you determine the jitter sensitivity you can specify this - so I get a number of incoming jitter, and a number for the OP THD and noise that is needed. So initially we were working with 4pS jitter, and 120dB THD and noise. No problem, the architecture met this requirement as you can create models to run simulations to show what the jitter will do - and you can run the model so onlyjitter is changed, nothing else. But then the requirements got changed to 15 pS jitter. Again, no problem, I simply redesigned the DAC and then achieved these numbers. So its easy to change the sensitivity by a factor of 4 just by design of the DAC itself - something that audio designers using chips can't do.

 

2. DAC type has a profound effect on performance. The most sensitive is regular DSD or PDM, where jitter is modulation dependent, and you get pattern noise from the noise shaper degrading the output noise, plus distortion from jitter. R2R DAC's are very sensitive as they create noise floor modulation from jitter proportionate to the rate of change of signal (plus other problems due to the slow speed of switching elements). I was very concerned about these issues, and its one reason I invented pulse array, as the benefit of pulse array is that the error from jitter is only a fixed noise (using random jitter source with no low frequency problems). Now a fixed noise is subjectively unimportant - it does not interfere with the brains ability to decode music. Its when errors are signal dependent that the problems of perception start, and with pulse array I only get a fixed noise - and I know this for a fact due to simulation and measurements.

 

3. The DAC degrades clock jitter. What is not appreciated is that master clock jitter is only the start of the problem. When a clock goes through logic elements, (buffers level shifters, clock trees gates and flip-flops plus problem of induced noise) every stage adds more jitter. As a rough rule of thumb a logic element adds 1 pS of more jitter. So a clock input of 1pS will degrade through the device to be effectively 4 pS once it has gone through these elements (this was the number from a device I worked on some years ago). So its the actual jitter on the DAC active elements that is important not the clock starting jitter.

 

The benefit I have with Pulse Array is that the jitter has no sound quality degrading consequences - unlike all other architectures - as it creates no distortion or noise floor modulation. Because the clock is very close to the active elements (only one logic level away), the jitter degradation is minimal and there are no skirting issues at all. This has been confirmed with simulation and measurement - its a fixed noise, and by eliminating the clock jitter (I have a special way of doing this) noise only improves by a negligible 0.5 dB (127 dB to 127.5 dB).

 

This is true of all pulse array DAC's even the simpler 4e ones. In short the jitter problem was solved many years ago, but I don't bleat on about it as its not an issue and because it's way too complex a subject to easily discuss.

 

Pulse Array is a constant switching scheme - that is it always switches at exactly the same rate irrespective of the data, unlike DSD, R2R, or current source DAC's. This means that errors due to switching activity and jitter are not signal dependent, and so is innately immune from jitter creating distortion and noise floor modulation and any other signal related errors. The only other DAC that is constant switching activity is switched capacitor topology, but this has gain proportionate to absolute clock frequency - so it still has clock problems.

 

I plan to publish more detailed analysis of this, but from memory all of my DAC's have a negligible 0.5dB degradation due to master clock jitter, so its a non issue.

 

And yes you are correct, the absolute frequency is quite unimportant, so forget oven clocks, atomic clocks etc. Also the clock must be physically close to the active elements,with dedicated stripline PCB routing with proper termination. Running the clock externally is a crazy thing to do, as you are simply adding more jitter and noise and an extra PLL in the system."

[romaz]

9 minutes ago, vortecjr said:

Barrows has already touched on what is taking place behind the scenes with John. While he is doing this on his own he is sharing the information with us. I also have something planned, but it has to wait until I have time. Anyway, I want to add that John is having to build very sensitive equipment just to prove his hypothesis. If it's this hard to measure then you have to really have faith that it matters as much as you think it does. Whatever is going on, if anything, is not at all obvious while other simple tweaks are. So what we are proposing is that people take care of the obvious things first since we can measure and substantiate them. Hopefully John finds something worth waiving the flag about.  

 

Jesus, fair enough.  Any measurements John comes up with will be trusted as properly done, however, whether they explain what I am hearing or not is irrelevant.  As a proud owner of your products, I will remind you of threads such as these and the conclusions they have drawn based on their measurements:

 

https://audiosciencereview.com/forum/index.php?threads/hardware-review-and-measurements-of-sonore-microrendu-v1-4.1867/

 

https://audiosciencereview.com/forum/index.php?threads/measurements-of-sonore-microrendu-streamer.577/

[romaz]

2 minutes ago, vortecjr said:

No one is saying that your observations are in valid. What we think is missing a basic understanding about what needs to be considered first and what matters the most. Barrows has been addressing some points of interest already. I only speak for Sonore, but we get blamed for everything and it's never your power supply, your speakers, your amp, or your ears:)  

 

As I have reported my findings, I have kept my power supply, speakers, amps and ears a constant.  I have never blamed you.  Not sure where that is coming from.

[romaz]

5 hours ago, barrows said:

I would suggest that, perhaps, this already exists.

 

Your bias and your agenda are quite obvious.

 

5 hours ago, barrows said:

Anyway, i have never bashed a component made by anyone.  I have suggested that some approaches, which may be used by some manufacturers are of questionable value: like using an external clock instead of using a good one internally.  Hey, look, Rob Watts, of Chord (a designer I respect very much) said the same thing...

 

Barrows, really, enough is enough.

 

You should know that Rob Watts doesn't think highly of the microRendu at all but at least he is willing to admit he doesn't know everything.  Because of the galvanic isolation he has implemented in his DACs and because his pulse array DACs are inherently immune to jitter, he believes all sources sound the same with his DAVE and that the microRendu is no better than a Windows laptop.  Here is what Rob shared with me last year shortly after I bought my microRendu and I told him I was hearing an improvement:

 

"Hmm, I am somewhat bothered by the idea that the microRendu is better than a windows (it must be windows) lap-top on batteries, as there is absolutely no explanation for why that may be. But "you know nothing Jon Snow" is my favourite quote for good reason; it reminds me that there are limits to one's knowledge."

If you are going to come on to the REF10 thread and publicly question the value of an external clock like the REF10 based purely on your theories, at least have the decency to listen to it first.  No one questions the value of using a good internal clock but sometimes, the components that we buy don't have the best internal clocks and that there are external clocks like the REF10 that are better.  Your continued bleating about how using an external clock is a bad idea makes you look ignorant when those of us who have experienced the REF10 first hand clearly believe differently.  Please, enough with the insults.

[romaz]

 

 

Jesus and Barrows, I will respond to your questions but this will be my last response.  Feel free not to respond back.  Chris, if you see fit to remove my post, I'm ok with it.

 

3 hours ago, vortecjr said:

Romas, so you don't like our message against the spaghetti solution and this makes you resort to attacking us and the microRendu. 

 

Jesus, it really doesn't matter to me at all whether you like this "spaghetti solution" or not.  It has nothing to do with it.  As far as attacking you, I'm not sure where your paranoia comes from.  As I see it, Sonore are the aggressors here.  I merely countered Barrows' narrow minded view about a product he has never even listened to.

 

4 hours ago, vortecjr said:

All of this research might actually prove you have super human hearing. 

 

Trust me, I don't have super human hearing.  What I'm hearing is being heard by many, you just refuse to acknowledge there may be something there.  It's interesting that you are waiting for measurements from John S. to validate the validity of clocking when you offer no measurements for your products.  The only measurements I see come from ASR and we all know what those look like.  Regardless, I didn't buy my microRendu or my REF10 because of measurements, I bought them for their potential to cause "goose bumps."  As far as I know, there is no lab instrument that can measure for this.  Sometimes, you just have to listen.

 

22 hours ago, barrows said:

In addition my posts are not meant to be any criticism of the Mutec components, for their intended purpose I expect they are excellent, and the clock itself, if it actually meets the claimed specs...

 

...if it actually meets the claimed specs???

 

Barrows, please give this manufacturer the benefit of the doubt that they have integrity in reporting their measurements.  At least, they offer measurements.  This is what I meant when I said that your bias and your agenda are clear.  You say your comments are not meant to be critical and then you follow it with a veiled insult.

 

3 hours ago, barrows said:

So who is "right", Rob Watts or you?  It appears that you and I both know something which Rob Watts does not, that the source still matters despite using a well isolated async USB interface?  We agree, so I am really unclear as to what your point here is.

 

Barrows, if you are going to extol the virtues of Rob's comments for your personal gain, you need to be prepared to defend his other comments.  My point with bringing Rob's comments up is that despite his intelligence, wisdom and experience, even Rob doesn't know everything but at least he is willing to admit it.  With regards to the REF10 and how it might impact a DAC or any other digital component, unless you've actually listened to what it can do, please keep your speculative comments to yourself.

 

4 hours ago, vortecjr said:

Anyway, Mr Watts is not fond of the microRendu and he thinks it's not better than a Windows laptop. I'm perfectly fine with that because we are making units that replace laptops and desktops in your audio room. Don't you think his statements about the microRendu also extends to the spaghetti solution being no better than a laptop?   

 

Yes, that's correct.  Rob does not believe the source matters with his DACs.  In other words, he believes all sources should sound the same based on the technology he has implemented in his designs and based on his own listening of various sources and so this would apply to this "spaghetti solution" as well.  To Rob's credit, however, as you read, he was clear to say he doesn't know everything and so you'll never find Rob coming onto a thread like this and questioning the findings of others.  Further to Rob's credit, he is actually willing to listen.  He approached me a while back and offered to fly to my home in California later this year to listen to my sources.  Obviously, I have agreed to host him as I welcome the opportunity.

 

https://www.head-fi.org/threads/chord-electronics-blu-mk-2-the-official-thread.831343/page-83#post-13679993

 

3 hours ago, barrows said:

As far as Sonore goes we make products to both achieve the convenience of computer audio, and to improve the performance of the associated DAC by providing as good a USB feed as possible at the associated price point. 

 

No argument here.  Sonore makes fine products.  Please let them speak for themselves.

 

Now moving back to the REF10, I have received more clock cables to try of varying price.  I will report back once I have had a chance to evaluate them...