Master Clock for your EtherREGEN

[Ricardo007]

Hello

Did anyone tried thé sotm master clock on ER ? 

[MartinT]

Yesterday I received my Black Ravioli Eflos grounding box, custom made for me with a BNC connector. I connected it to the OCXO clock. The sound is cleaner! There is less noise and it is noticeably crisper in the delivery of complex music. Certain strands of music are no longer obscuring others. There is more air around acoustic guitars. The noise floor is definitely lowered again.

This proves that there is still some residual ground plane noise worth mopping up in the OCXO. This little clock, and overall system performance, keeps getting better and better.

[Morph]

Interesting thread,
PM'd you @MartinT

[Clockmeister]

15 hours ago, Ricardo007 said:

Hello

Did anyone tried thé sotm master clock on ER ? 

 

Yes I have performed this task and can report it is a positive outcome, specifically with the sound staging and gives a more relaxed feel to the overall presentation.

[Clockmeister]

Hello Superdad

 

Like your products very much by the way 😎

 

With regard to the Crystek 575 clock, are you looking to replace this item in any up and coming re-engineering of the Ethernet regen at all?

 

While the specifications are quite good I have noticed a fair amount of harmonic noise does extended well into the 2Ghz territory in numerous products that use this device, which may possibly have an effect on surrounding circuitry?

 

Not a critique' just an observation.

 

Regards

 

DM

 

[Superdad]

3 hours ago, Clockmeister said:

Hello Superdad

Like your products very much by the way 😎

Thank you very much!

 

Quote

With regard to the Crystek 575 clock, are you looking to replace this item in any up and coming re-engineering of the Ethernet regen at all?

We have no plans to replace the Crystek 575 in the current EtherREGEN.

We have on paper an extremely elaborate future design (likely $2K-$3K), but with other projects in front of it I am sure it could be a year or more until release. Such would likely incorporate a much more expensive clock. (Remember, even at OEM 100+ pieces, the really good phase-noise OCXOs start at $350 for the part. Sorry, not going to screen surplus clocks or buy questionable Chinese OCXO production.)

 

Quote

While the specifications are quite good I have noticed a fair amount of harmonic noise does extended well into the 2Ghz territory in numerous products that use this device, which may possibly have an effect on surrounding circuitry?

I can tell from some of your posts in other threads that you are technical person with some design experience, so I will not dismiss your comment. Such should be addressed by @JohnSwenson as I am out of my depth here.  But harmonic noise in 2GHz range? Surely you are not referring to any phase-noise in that region. Is this some property of AT-cut crystals as used in XO versus SC-cut typical in OCXO? I have read a little on various crystal cuts and have not seen reference to such noise. Is this something you have measured?

 

Do remember that in EtherREGEN we utilize a precision clock synthesizer (we need 4 separate clock lines, 2 each at 25MHz and 250MHz) and run all clock lines as LVDS (differential). That's something you rarely see even in top-dollar DACs. 

[JohnSwenson]

5 hours ago, Clockmeister said:

Hello Superdad

 

Like your products very much by the way 😎

 

With regard to the Crystek 575 clock, are you looking to replace this item in any up and coming re-engineering of the Ethernet regen at all?

 

While the specifications are quite good I have noticed a fair amount of harmonic noise does extended well into the 2Ghz territory in numerous products that use this device, which may possibly have an effect on surrounding circuitry?

 

Not a critique' just an observation.

 

Regards

 

DM

 

What signal are you refering to that has 2GHz harmonics? If it is the clock signal itself, then yes, the harmonics go up quite high, that is on purpose, it is after all a square wave, the only way to get a good square wave is lots of high frequency harmonics. The higher the harmonics the faster the rise time and the lower the jitter.

 

If you are referring to high frequencies on other signals, there are circuit implementation details to prevent that from happening. I spent a lot of effort in the EtherREGEN to keep those as low as possible. It is an interesting engineering trade off. The faster the clock edges the lower the jitter, but the higher the ground-plane noise you get from the circuitry operating with those fast edges. I have endeavored to find a good trade off between this that gives the lowest overall jitter in the output stream.

 

John S.

[jamesg11]

Awaiting Clockmeister’s rejoinder ...

[Clockmeister]

Hello John

 

Thank you for replying always nice to hear the thoughts of the main designer's rational for the end product.

 

Indeed the faster the rise time on the leading edge the more desirable the accuracy of the potential jitter reduction as you have pointed out the harmonic content stretches higher up into the upper frequency domains. The Crystek 575 series does feature harmonics orders way over the 40th again dependant on fundamental frequency.

 

Some of the harmonics are not 'down in the mud' (say only -45dbm or lower) from the core number and are quite prevalent at frequencies that could interfere with logic controllers/FPGA' s/ power control circuits and regulation etc

 

Your very genuine and honest reply regarding a trade off of the best possible situation against clock accuracy (jitter attenuation/phase noise/ground bounce and potential contamination of surrounding circuit pathways and i/c devices is refreshing good.

 

One must also take into account the cost of the device and all these factors together and as I mentioned in my first post on this thread a nice product that works and very fair price a nice job John.

 

My thoughts are specifically geared towards the  Crystek clocks (usually because the specs do not tell the whole story) in the area of audio, having pretty decent experience of this oscillator in many audio applications and in each case improving the end sound quality by replacing the Crystek with a clock with a not so (theoretical) desirable leading edge definition yet much improved waveform width definition and reduced overshoot , more stable pulse width and obtained a far more beneficial end result in sound quality

 

Appreciate every situation andbinstallion is different John, however with today's densely packed, high performing low form factor packages with ever square mm accounted for compromises are made.

 

One overriding factor has come out of my many years experience with high speed serial data work is the quality of the power lines and incoming  power quality feeding the clock is as important if not more so than the specification of the clock itself.

 

One point you have made on this thread which many people would not have paid attention to is impedance matching of cables and circuit pathways and that signal reflections (transitions of signals  bouncing back and forth a defined number of times according to cable length, /LCR connector mis matches) does have a significant effect on the sound quality especially with any digital signal transfer interfaces and  clock data transmission lines

 

If I have time over the weekend I could set up a demonstration of 50 and 75 ohm cable connection resultant  mismatches and the effects on the waveform at the input connector of the device, also show how a 50/75 terminator doesn't really cure the problem and that genuine matched impedance terminations are the most desirable methods of achieving accurate results. Though again I appreciate that not all audio equipment is geared up for this premise as with everything that is built to price compromises are made.

 

DM

 

 

[Ricardo007]

On 6/25/2020 at 8:27 PM, Clockmeister said:

 

Yes I have performed this task and can report it is a positive outcome, specifically with the sound staging and gives a more relaxed feel to the overall presentation.

Hello Meister

I read from Alex Crespi from UpTone Audio that thé etherregen likes to see square waves and not sinewaves that's thé reason I asked thé question, thé Sotm master clock being sinewaves... I also have other SoTM products to "discipline" (but not in à dungeon) so I thought better for them to have an SoTM master... 

Actually hesitating to buy between Sotm Mutec and Cybershaft

Any help ? 🐸

[JohnSwenson]

The 575 does have its own dual regulated supply, and the only thing it drives is the clock synthesizer (which has its own regulators) which only outputs LVDS signals. All clock distribution is carefully impedance matched differential pairs (I had a special board stackup used that allowed continued impedance matching as pairs changed layers). The reclocking flops are fully differential including clock. The chips which have a single ended clock input have  a very low additive phase noise LVDS to CMOS converter right next to the clock pin. The result of all this is a system that is much less sensitive to ground noise than is usually seen.

 

That was really the whole reason for the EtherREGEN, produce much less ground plane noise in the first place, and have circuitry much less sensitive to what ground plane noise that is there. Unfortunately I can't do anything about what is inside the chips themselves. I spent 30 years designing power networks inside large high speed chips, I have a VERY good feeling for what that can do to jitter for the circuitry inside a chip. Unfortunately we can't afford to do a full custom chip for every function we need, so all I can do is choose ones where it looks like someone did a fairly decent job on the internal PG networks.

 

John S.

[Clockmeister]

41 minutes ago, JohnSwenson said:

The 575 does have its own dual regulated supply, and the only thing it drives is the clock synthesizer (which has its own regulators) which only outputs LVDS signals. All clock distribution is carefully impedance matched differential pairs (I had a special board stackup used that allowed continued impedance matching as pairs changed layers). The reclocking flops are fully differential including clock. The chips which have a single ended clock input have  a very low additive phase noise LVDS to CMOS converter right next to the clock pin. The result of all this is a system that is much less sensitive to ground noise than is usually seen.

 

That was really the whole reason for the EtherREGEN, produce much less ground plane noise in the first place, and have circuitry much less sensitive to what ground plane noise that is there. Unfortunately I can't do anything about what is inside the chips themselves. I spent 30 years designing power networks inside large high speed chips, I have a VERY good feeling for what that can do to jitter for the circuitry inside a chip. Unfortunately we can't afford to do a full custom chip for every function we need, so all I can do is choose ones where it looks like someone did a fairly decent job on the internal PG networks.

 

John S.

Hello John

 

I would expect nothing less and good engineering principles for eliminating as much internal electrical and outside connective signal noise as possible. Though as you say you can only address all of the potential hot spots you have identified within the remit of projects budget and the fact you have paid attention to ground plane noise is good, so many audio designers do not feel it relevant to pursue this avenue. So appreciate your more wide band approach to this product.

 

Rolling your own chips best solution however budgets way above this products pay grade I feel.

 

 

 

 

[Clockmeister]

7 hours ago, Ricardo007 said:

Hello Meister

I read from Alex Crespi from UpTone Audio that thé etherregen likes to see square waves and not sinewaves that's thé reason I asked thé question, thé Sotm master clock being sinewaves... I also have other SoTM products to "discipline" (but not in à dungeon) so I thought better for them to have an SoTM master... 

Actually hesitating to buy between Sotm Mutec and Cybershaft

Any help ? 🐸

Good Morning Ricardo:

 

There are usually two forms of audio clock outputs either a clipped sine wave or square wave each has there uses and applications.

 

In my experience with many audio devices I have found that not all products from the same stable produced the most desired results from a wide range of manufacturers and not just digital audio either.

 

I am fortunate to have access to dedicated test lab as well as some respectable audio equipment. I do personally own all of the above clocks you have mentioned including a Cyber shaft OPA21 and a Mutec ref 10 SE-120 plus a coupe of custom 10 Mhz units.

 

All of the above clocks have a positive effect to sound quality when used in the context of streamer/CD/PC DOB <> dac's/processors some greater than others.

 

With regard specifically to ether regen as  master word clock signal, again they all have a positive effect without question *caveat* if you run a high quality headphone set up, you results will be more intimidate with speakers it can be more subtle depending on the resolution of the system it is being used in.

 

Benefits can include but exclusive to, improved sound staging and stage depth, spatiality and instrument separation. Bass texture and detail is better along with a tighter feel to the bass and improved coherence. These have been my personal experience.

 

 

 

 

[LowMidHigh]

4 hours ago, Ricardo007 said:

Hello Meister

I read from Alex Crespi from UpTone Audio that thé etherregen likes to see square waves and not sinewaves that's thé reason I asked thé question, thé Sotm master clock being sinewaves... I also have other SoTM products to "discipline" (but not in à dungeon) so I thought better for them to have an SoTM master... 

Actually hesitating to buy between Sotm Mutec and Cybershaft

Any help ? 🐸

Isn't Mutec the only one with a square wave? If so, and given that according to John that' shape is optimal the ER, then you have your answer. 

[Clockmeister]

For those interested in how not to implement a Crystek 575 clock correctly images below clearly show a before and after working out exactly what was amiss with this particular 100Mhz 575 clock in a well known digital to analogue converter. As you can clearly see, the quite high amplitude harmonic noise sitting on the analogue output of said dac before extending to 2Ghz and beyond. limited the span to 2Ghz although it extend up to 2.6Ghz but the amplitude was much lower. Although the images are only 30 seconds apart the solution had been worked out over a couple of days.

 

So before and engineering solutions were applied

 

 

 

 

 

 

This was after the solution was applied.

 

 

 

 

In this instance a three way approach was need to remove the bulk of the harmonic distortions, looking at both incoming ac, dc rail filtration and RF shielding methods

[audiotunesx]

Lot's of great insight in this thread, many thanks I learned a lot.

 

The BG7TBL/DAPU clock is a very interesting solution.  We'd have some control over the sound because we have an assortment of power supplies that we can use to match the needs of our systems. I messaged the fellow HamRadioshop on the original aliexpress link days ago.  He got back to me today and said that he can make a 75 ohm version!  So cost would be $125 unit + $475 for say an sbooster mkii, so $600 CAD.  Not bad.  I wish the LPS 1.2 had the power, but the JS-2 would be the ideal PSU I'd imagine (power both the eR and clock with it).  I've had the $99 ifi 12v plug providing 18watts without issue to my NAS, so one could potentially get away with that for experimentation.

 

Teac 10m.  This has only 50 ohm outputs.  Inside, the transformer is quite small.  Beautiful casing, and I'm sure it will last.  A simple comparison is here:  https://dime.jp/genre/604669/  (use Chrome for auto-translate).  There's a ton of foreign reviews.  It seems that it can improve imaging and soundstaging as expected by a clock but only to an extent.  Teac Direct on eBay has a few open box clocks.  They are taking offers.  To get this to work Cybershaft has a 75 ohm to 50 ohm adapter that would connect to the eR.  They also have 2 50 ohm cable options, both very reasonable cost.  The review above reviews the basic cable, and they seem to have liked it.  Almost all reviews are with the associated Teac dac, or a Esoteric.  There's a youtube review with before/after audio footage.  I don't hear that big of a change.  Same reviewer has before/after with the Bonn N8, much bigger change.  Cost (CAD) $1400 open box + $150 for cybershaft accessories.  I think this would be worth it if my dac could use the external clock as well.  From what I gather, cascading a second eR would likely have a greater effect or a Farad power supply with a reasonable cable at much less cost.

 

Cybershaft Op-14.  Prices have gone up a lot over the last two years.  Now about the same as Teac retail.  The review says it provides more than the Teac but sounds sharp.  Inside looks to be an R core transformer.  The clock itself is shielded but looks to be a Chinese 4G clock as well.  Big capacitors near the clock must help, but I do wonder if we give the BG7TBL/DAPU clock a mid or top range power supply how close it would get to the low range Cybershaft solution.

 

Mutec - sounds like it has the right sound qualities for my taste.  With that price though, I'd wait for the Uptone ClockRegen.

 

I might just hop on MartinT's bandwagon and go with the BG7TBL/DAPU clock with 75 ohm terminals for now.  Entry level 75 ohm BNC cables actually seem reasonably priced.  1m Wireworld's Chroma is only $30 USD, Starlight 8 $100, Cardas Parsec $140.

 

I'd really like to know:

- How hot does the BG7TBL get?  Does it need a lot of ventilation?

- Does it increase sibilance, harshness, or make the sound forward?  Any change to warmth, or the treble/bass balance of the sound?

[Clockmeister]

I am sure Martin T will be able to enlighten you on how his BG7TBL clock helps in his system.

 

Below is a an image of one of those very 10Mhz clocks using a  75 Ohm 0.5m bnc lead being measured at 50Ohm (using the 50 ohm output on the clock)  you can clearly see the impudence mismatch and the resultant distorted square wave form.

 

Followed by a eye diagram again clearly visible is the cable mismatch finally the FFT plot of the resultant harmonic noise.

 

These clocks offer a respectable upgrade for your ether regen I would suggest the use of a ultra low noise power supply is essential with this device to bring out its potential.

 

 

 

 

 

 

[MartinT]

1 hour ago, audiotunesx said:

I'd really like to know:

- How hot does the BG7TBL get?  Does it need a lot of ventilation?

- Does it increase sibilance, harshness, or make the sound forward?  Any change to warmth, or the treble/bass balance of the sound?

 

Glad to have got people thinking about the BG7TBL.  It was just an experiment but turns out to require no apology whatsoever, its performance is astonishing for the money.

 

Answers:
1) the outer case gets hardly even tepid to the touch.  There is plenty of air inside and no special ventilation required.  The OCXO is ready inside one minute and I leave mine switched on.

2) no, it greatly increases soundstage width and depth, air and space, rhythmic intensity.  I have not noticed any more forwardness but I have noticed backing singers or rear of orchestra appear far behind the plane of the speakers.  Amazing depth.  The natural balance of my system is unchanged but bass has taken on additional potency and extension such that air movements and infra-bass come through more clearly, sometimes shaking the room.  My speakers are not lacking in bass ability.

[jamesg11]

1 hour ago, audiotunesx said:

I messaged the fellow HamRadioshop on the original aliexpress link days ago.  He got back to me today and said that he can make a 75 ohm version!  So cost would be $125 unit

Appreciated if you could give a link to this!

[audiotunesx]

23 minutes ago, MartinT said:

 

Glad to have got people thinking about the BG7TBL.  It was just an experiment but turns out to require no apology whatsoever, its performance is astonishing for the money.

 

Answers:
1) the outer case gets hardly even tepid to the touch.  There is plenty of air inside and no special ventilation required.  The OCXO is ready inside one minute and I leave mine switched on.

2) no, it greatly increases soundstage width and depth, air and space, rhythmic intensity.  I have not noticed any more forwardness but I have noticed backing singers or rear of orchestra appear far behind the plane of the speakers.  Amazing depth.  The natural balance of my system is unchanged but bass has taken on additional potency and extension such that air movements and infra-bass come through more clearly, sometimes shaking the room.  My speakers are not lacking in bass ability.

 

Thanks MartinT, I went ahead and placed an order and requested DAPU/75 ohm.  Really appreciate your insights, this will be fun to try!

 

jamesg11, the original link still works: https://www.aliexpress.com/item/4000152539910.html?spm=a2g0s.9042311.0.0.795e4c4dGTiyce

 

First time ordering from that site.  They didn't accept PayPal for Canadian addresses, but their system does use the extra layer of mastercard verification.  There is an 'add a message' section on the order form where you can put in a note for DAPU/75 ohm.  I also messaged the seller afterwards with the order number and the DAPU/75 ohm request.  I'll report back once I get the item, might be a while.

[Superdad]

Well AliExpress is very easy for me (order things from AliExpress and Alibaba all the time). Much easier that the Chinese-only Taobao.com.

 

So I just went ahead and ordered one of these BG7TBL units to try.  

 

Because really, nobody can purchase new those DAPU O55A OCXOs for even 1/4th the price they are getting for the whole box (with 4G tower reclaimed clocks).

I did receive a solicitation from a fellow in China offering to sell us unlabeled low-phase noise OCXOs (typical -130dBc/Hz at 10Hz for 10MHz version) for $100 each at 250 piece quantity order. But even if we take samples and test (John now has $18K Jackson Labs Phase-Station to do that! ), there is no guarantee that production parts would be consistently as good as the samples--and plotting/sorting ever part is out of the question for any sort or reasonable price product. Takes WAY too much time--set-up, warm-up, etc.  That's what Cybershaft offers with their graded units--for which each one comes with its own phase-noise plot.

[audiotunesx]

I've had good experiences with Oyaide in the past and decided to go with the AS-808B V2 BNC cable to test with the BG7TBL.  Cable Company doesn't stock this, so bought from an eBay store for $90 CAD shipped.  The silver DB-510 seems fairly well received and also good value.  If the BG7TBL works out, but the copper cable makes it too dark, I'll test the DB-510 afterwards.

 

Another low cost option that came up in some old threads is the Canare 12G-SDI, $27 USD.  If for some reason the Oyaide copper is bright, I'll give this one a try.  

https://www.bhphotovideo.com/c/product/1338226-REG/canare_cal55cuhd003_12g_sdi_4k_uhd_single_channel_bnc_cable.html

[LowMidHigh]

7 hours ago, audiotunesx said:

Lot's of great insight in this thread, many thanks I learned a lot.

 

The BG7TBL/DAPU clock is a very interesting solution.  We'd have some control over the sound because we have an assortment of power supplies that we can use to match the needs of our systems. I messaged the fellow HamRadioshop on the original aliexpress link days ago.  He got back to me today and said that he can make a 75 ohm version!  So cost would be $125 unit + $475 for say an sbooster mkii, so $600 CAD.  Not bad.  I wish the LPS 1.2 had the power, but the JS-2 would be the ideal PSU I'd imagine (power both the eR and clock with it).  I've had the $99 ifi 12v plug providing 18watts without issue to my NAS, so one could potentially get away with that for experimentation.

 

Teac 10m.  This has only 50 ohm outputs.  Inside, the transformer is quite small.  Beautiful casing, and I'm sure it will last.  A simple comparison is here:  https://dime.jp/genre/604669/  (use Chrome for auto-translate).  There's a ton of foreign reviews.  It seems that it can improve imaging and soundstaging as expected by a clock but only to an extent.  Teac Direct on eBay has a few open box clocks.  They are taking offers.  To get this to work Cybershaft has a 75 ohm to 50 ohm adapter that would connect to the eR.  They also have 2 50 ohm cable options, both very reasonable cost.  The review above reviews the basic cable, and they seem to have liked it.  Almost all reviews are with the associated Teac dac, or a Esoteric.  There's a youtube review with before/after audio footage.  I don't hear that big of a change.  Same reviewer has before/after with the Bonn N8, much bigger change.  Cost (CAD) $1400 open box + $150 for cybershaft accessories.  I think this would be worth it if my dac could use the external clock as well.  From what I gather, cascading a second eR would likely have a greater effect or a Farad power supply with a reasonable cable at much less cost.

 

Cybershaft Op-14.  Prices have gone up a lot over the last two years.  Now about the same as Teac retail.  The review says it provides more than the Teac but sounds sharp.  Inside looks to be an R core transformer.  The clock itself is shielded but looks to be a Chinese 4G clock as well.  Big capacitors near the clock must help, but I do wonder if we give the BG7TBL/DAPU clock a mid or top range power supply how close it would get to the low range Cybershaft solution.

 

Mutec - sounds like it has the right sound qualities for my taste.  With that price though, I'd wait for the Uptone ClockRegen.

 

I might just hop on MartinT's bandwagon and go with the BG7TBL/DAPU clock with 75 ohm terminals for now.  Entry level 75 ohm BNC cables actually seem reasonably priced.  1m Wireworld's Chroma is only $30 USD, Starlight 8 $100, Cardas Parsec $140.

 

I'd really like to know:

- How hot does the BG7TBL get?  Does it need a lot of ventilation?

- Does it increase sibilance, harshness, or make the sound forward?  Any change to warmth, or the treble/bass balance of the sound?

 

I'm a lowly layman, who is guided by John"s views on such matters. 

 

As I mentioned above, according to John, the ER, as other audio equipment, is designed around a square wave signal. You may want  to take that into account. 

 

In addition, as he explains in a different thread, the 75/50 ohm adaptors and toggles, as Cybershat employs, are ineffective and don't perform as intended. That topic was discussed when a proposal of equipping the ER with said toggle was floated up and   summarily rejected. I suppose Mutec offers two batteries of BNC ports, 50ohn and 75ohm respectively, for that reason. 

[MartinT]

6 hours ago, audiotunesx said:

Another low cost option that came up in some old threads is the Canare 12G-SDI, $27 USD.

 

I'm using 0.5m Canare LV-61S 75 ohm cables to very good effect.

[MartinT]

6 hours ago, LowMidHigh said:

As I mentioned above, according to John, the ER, as other audio equipment, is designed around a square wave signal. You may want  to take that into account.

 

I'm using the BG7TBL squarewave output into the ER.