John Swenson tutoring paper: "Considerations regarding usage of external reference clocks" (EtherREGEN and other): Sine vs. square, impedance, cables—and a money saving surprise at the end.

LowMidHigh · March 27, 2021

9 minutes ago, MartinT said:

It's really the Belden 4694R that should be compared with the Canare LV-77S. And they sound really close albeit slightly different in character.

1694A is a lesser cable and sounds inferior.

Thanks for the guidance, Martin.

Indeed, the 4694R measures better than the 1694A.

How flexible is the 4694R? The 1694A is rather stiff, whereas the Canare very pliable.

James Stephens · March 27, 2021

Specs for the Belden 4794R are here: https://catalog.belden.com/techdata/EN/4794R_techdata.pdf

It has even better attenuation vs frequency characteristics than Belden 1694A and 4694R.

Martin just triggered my memory that Alex shared some info on where to get this cable offering back in October:

No telling what will sound best in your system with your ears.

Best,

James

Superdad · March 27, 2021

16 minutes ago, MartinT said:

1694A is a lesser cable and sounds inferior.

You too Martin. Please let's not divert this thread into clock cable chatter--at least not so early. Don't want to confuse or scare folks off!

(Especially since one of the main points of the paper is that with sine waves and a filter the clock cable quality almost ceases to matter!)

Thanks,

--Alex C.

LEO SOUND · March 27, 2021

If square wave outputs are to be avoided, why the etherregen is "square wave" and therefore you have to buy a sin wave clock with a filter to be sure to have a good signal.
I'm interested in a Square Wave from AfterDark that claims it's special for etherregen on their website.

@AfterDark.Can you provide details on this clock as it looks like it was produced in collaboration with Uptone Audio.
But from the white booklet, we just have the impression that we need Sine Wave because almost no clock does a good Square Wave except the very expensive watches and out of budget for me.

Sotm is sine wave I think.

LowMidHigh · March 27, 2021

1 hour ago, LEO SOUND said:

If square wave outputs are to be avoided, why the etherregen is "square wave" and therefore you have to buy a sin wave clock with a filter to be sure to have a good signal.
I'm interested in a Square Wave from AfterDark that claims it's special for etherregen on their website.

@AfterDark.Can you provide details on this clock as it looks like it was produced in collaboration with Uptone Audio.
But from the white booklet, we just have the impression that we need Sine Wave because almost no clock does a good Square Wave except the very expensive watches and out of budget for me.

Sotm is sine wave I think.

It's not true that a square wave is to be shunned. Here's what the paper says:

"Just remember that the best possible result is still going to be using a square wave clock box with a REALLY good sine to square converter, everything being just right inside the box—AND you use a really low-attenuation-with-frequency cable."

Superdad · March 27, 2021

5 hours ago, LEO SOUND said:

If square wave outputs are to be avoided, why the etherregen is "square wave"...

[I will probably state this with slightly wrong terms but conceptually its about right.]:

Clocks exist in digital circuits for the chips to time everything they do from. The chips have to "trigger' off the incoming clock at some set voltage point of whatever the clock's waveform is. The easiest and most accurate (time/spacing/phase-wise) for a device to clock off of is a square-wave, because ideally its rising voltage is straight up at its frequency intervals--it's square-ish! As John explains in the paper delivering a really good square wave is harder than delivering a good sine wave (and filtering it so that the inevitable harmonics don't disrupt the accuracy for the target device.

So it is not just the EtherREGEN that prefers a square wave--all digital circuits do.

[Which is not to say that a smart designer couldn't put a really good sine>square converter at the input of their device. We could have with the EtherREGEN but the really good one we like needs more power supply current that we could provide on the 'B' side with this design. Alternatively, Mini-Circuits makes a PCB-mount version of the exact same filter as the one we are recommending. But it is physically very large and there is no room for it on the EtherREGEN board.]

Quote

...and therefore you have to buy a sin wave clock with a filter to be sure to have a good signal.

It's just an easy way to assure good performance from a sine wave clock and to save you money on heavily-shielded clock cables.

Quote

I'm interested in a Square Wave from AfterDark that claims it's special for etherregen on their website.

@AfterDark.Can you provide details on this clock as it looks like it was produced in collaboration with Uptone Audio.

There was no collaboration on development between AfterDark and UpTone on their clocks.

AfterDark is a successful dealer for UpTone, they sell a lot of EtherREGEN and JS-2s, they also sell Cybershaft and have gotten that firm interested in EtherREGEN and JS-2 for Japanese market. That is the extent of collaboration between us.

Quote

But from the white booklet, we just have the impression that we need Sine Wave because almost no clock does a good Square Wave except the very expensive watches and out of budget for me.

Well it seems you got the point then. Doing a good square wave takes care--and then the clock cable matters a great deal. Going sine is easier and more budget-friendly.

Quote

Sotm is sine wave I think.

Talk about out of budget! If you are going to spend upwards of $4,000 on clock, you could buy a proven Mutec REF10 or top model Cybeshaft.

5 hours ago, LowMidHigh said:

It's not true that a square wave is to be shunned. Here's what the paper says:

"Just remember that the best possible result is still going to be using a square wave clock box with a REALLY good sine to square converter, everything being just right inside the box—AND you use a really low-attenuation-with-frequency cable."

Right. It is just that knowing and doing that all just right is neither a given, nor is it cheap. Don't know that that needs to be repeated too many times as the paper speaks for itself (or should I say for @JohnSwenson).

Exocer · March 28, 2021

Thank you @JohnSwensonand @Superdad. I learned a lot from this paper.

I'm going to ask a different question than the ones i've observed so far.

As an owner of the square wave output BG7TBL, I am now interested in bypassing the sine to square wave conversion circuitry after reading the paper.

The pin diagram of these OCXOs is fairly straight forward, however, it would be nice to find a small decent quality PCB board that would allow me to solder the OCXO from the BG7TBL (since at least the clock appears to be relatively decent for the investment on paper) for a complete sine-wave output or two via BNC outputs. Also a 2.1/5.5mm DC input on said board would be great.

Something like this (Option C without the block) but would fit the 51x51mm OCXO. It has 3 BNC outputs and appears there is no additional circuitry:

https://www.tindie.com/products/analysir/10mhz-ocxo-frequency-standard-module-or-kit/

Edit: I forgot my question.... Do you know of any module kits/PCBs one could drop the FE-180/DAPU clock into?

R1200CL · March 28, 2021

5 hours ago, Superdad said:

Would have been better just to run the OXCO module in the thing straight to a BNC jack.

Maybe a mod we can do our self 😀

@Exocer

Please share where to connect.

R1200CL · March 28, 2021

3 hours ago, Superdad said:

Which is not to say that a smart designer couldn't put a really good sine>square converter at the input of their device. We could have with the EtherREGEN but the really good one we like needs more power supply current that we could provide on the 'B' side with this design.

I love to see that smart designer doing just that 😀

And dual power input on EtherRegen MKII, as hopefully reduce the cost of the unit itself.
And of cause B side SFP28....(accepting any SFP).
A side is enough with one SFP as well if you ask me.

So actually a pure SFP+ reclocker with external 50 ohm sine input.

3 hours ago, Superdad said:

Alternatively, Mini-Circuits makes a PCB-mount version of the exact same filter as the one we are recommending. But it is physically very large and there is no room for it on the EtherREGEN board.

I wouldn’t mind you tell us how to implement as DIY. If even possible?

JohnSwenson · March 28, 2021

47 minutes ago, R1200CL said:

I wouldn’t mind you tell us how to implement as DIY. If even possible?

It is actually very easy to implement a mod to just feed the sine wave out of the OCXO to the BNC jack. I don't have the time to take the box apart and take photos etc.

The concept is:

Use Xacto knife to cut the trace coming off the output pin from the OCXO

Unsolder (or cut pins) of the voltage regulator driving everything except the OCXO

cut the wire going from the board to the BNC jack

Solder another wire from the OCXO pin to the BNC jack.

Presto the sine wave from the OCXO goes directly to the BNC jack.

This bypasses all the circuitry on the board.

John S.

R1200CL · March 28, 2021

On 3/27/2021 at 12:08 AM, Superdad said:

inexpensive item charges $120 for shipping to destinations outside the USA.

Seems they changed their mind. (Can also be ordered from UK).

Not that $41 is that cheap. Will be interesting to see @AfterDark. price.

DSK6 · March 28, 2021

So have those of us who waited a while for the paper from John/Alex but then figured their workload wasn't going to allow them to release it any time soon and went ahead and ordered the After Dark Queen 75ohm Square Wave "special for EtherREGEN" clock not got the best model for the money what we thought we were getting?

Though nothing was stated explicitly anywhere, I must admit that due to the relationship between After Dark and Uptone and the fact that this model clock is advertised as the "special for EtherREGEN" model, I assumed that there had been at least some collaboration or discussion and that the square wave option was what Uptone and AfterDark were recommending for the EtherREGEN.

My AfterDark clock & PSU arrived in Australia last week, as did my Apogee Wyde-eye 75ohm BNC cable, and my EtherREGEN arrives tomorrow. Should we have bought a sine wave model OCXO clock and a filter instead? Or is the AfterDark Queen square wave output one of the ones that is done really well and (with good enough BNC cable) can match the sine wave output with filter at EtherREGEN?

I'm guessing I'm not alone in this situation or state of confusion.

Any feedback from AfterDark and Uptone would be appreciated as I'm not going to have a sine wave clock and filter to compare to.

GMG · March 28, 2021

Would this filter work?

https://www.crystek.com/microwave/spec-sheets/filter/CLPFL-0010-BNC.pdf

LEO SOUND · March 28, 2021

38 minutes ago, DSK6 said:

So have those of us who waited a while for the paper from John/Alex but then figured their workload wasn't going to allow them to release it any time soon and went ahead and ordered the After Dark Queen 75ohm Square Wave "special for EtherREGEN" clock not got the best model for the money what we thought we were getting?

Though nothing was stated explicitly anywhere, I must admit that due to the relationship between After Dark and Uptone and the fact that this model clock is advertised as the "special for EtherREGEN" model, I assumed that there had been at least some collaboration or discussion and that the square wave option was what Uptone and AfterDark were recommending for the EtherREGEN.

My AfterDark clock & PSU arrived in Australia last week, as did my Apogee Wyde-eye 75ohm BNC cable, and my EtherREGEN arrives tomorrow. Should we have bought a sine wave model OCXO clock and a filter instead? Or is the AfterDark Queen square wave output one of the ones that is done really well and (with good enough BNC cable) can match the sine wave output with filter at EtherREGEN?

I'm guessing I'm not alone in this situation or state of confusion.

Any feedback from AfterDark and Uptone would be appreciated as I'm not going to have a sine wave clock and filter to compare to.

As a future customer, I asked your question because I found it to be vague and "misleading".
Kind of like pulling out of the hat this new sine wave filter, I read a lot and why it hasn't been said before for those who want to make a choice.
I understood that if the square wave is well designed then it is the best choice for the RE. Otherwise you need a sine wave with this filter.
According to afterdark's response, your clock's square wave is at its best. so no worries for you.
if you want square wave and better data than the afterdark, you have to buy a mutec.

I quote the answer d' @AfterDark.:

"Hi Leo Sound,

Thanks for your question. The Giesemann Clock - Queen Square Wave Special Edition is special made by OCXO manufacture natively (OCXO module that has a built-in squarer circuit). So, there is no extra convertor outside the OCXO. This approach can make sure the OCXO can generate the best square wave for EtherREGEN.

Have a nice weekend.

Best Regards,

Adrian

AfterDark.""

Superdad · March 28, 2021

52 minutes ago, GMG said:

Would this filter work?

https://www.crystek.com/microwave/spec-sheets/filter/CLPFL-0010-BNC.pdf

It will. It's down a little more right at 10MHz (compared the 11MHz lowpass of the Mini-Circuits) but that should not be any problem. It is quite a steep filter. I thought the Crystek one was going to be a lot more expensive and a custom order item, but I see that Digikey has a few in stock for just $37 each.

Superdad · March 28, 2021

5 hours ago, Exocer said:

The pin diagram of these OCXOs is fairly straight forward, however, it would be nice to find a small decent quality PCB board that would allow me to solder the OCXO from the BG7TBL (since at least the clock appears to be relatively decent for the investment on paper) for a complete sine-wave output or two via BNC outputs. Also a 2.1/5.5mm DC input on said board would be great.

....Do you know of any module kits/PCBs one could drop the FE-180/DAPU clock into?

For $19 you could try this board:

https://www.ebay.com/itm/OCXO-adjust-PCB-Power-supply-voltage-12V-suitable-for-51X51-51X41-package/313123416940?

But desoldering the OCXO from the BG7TBL board may not be terribly easy depending upon how tight those holes are since you have to get all the solder connections to let go so that you can pull the part. Attempt at your own risk and please don't ask me anything about the above linked board. I just found it on the net and looks to be clean and simpler--a lot simpler than all the unnecessary circuitry that is on the BG7TBL boards.

LEO SOUND · March 28, 2021

the next Uptone Audio product will be a Square wave perfect external clock in an aluminum case with the most beautiful effect like Uptone JS2.😋

GMG · March 28, 2021

33 minutes ago, Superdad said:

It will. It's down a little more right at 10MHz (compared the 11MHz lowpass of the Mini-Circuits) but that should not be any problem. It is quite a steep filter. I thought the Crystek one was going to be a lot more expensive and a custom order item, but I see that Digikey has a few in stock for just $37 each.

Yes, I also saw it in Digikey with reasonable price and shipping to my location.

by the way, would a band pass filter be a better choice?

AfterDark. · March 28, 2021

On 3/27/2021 at 11:07 PM, DSK6 said:

So have those of us who waited a while for the paper from John/Alex but then figured their workload wasn't going to allow them to release it any time soon and went ahead and ordered the After Dark Queen 75ohm Square Wave "special for EtherREGEN" clock not got the best model for the money what we thought we were getting?

Though nothing was stated explicitly anywhere, I must admit that due to the relationship between After Dark and Uptone and the fact that this model clock is advertised as the "special for EtherREGEN" model, I assumed that there had been at least some collaboration or discussion and that the square wave option was what Uptone and AfterDark were recommending for the EtherREGEN.

My AfterDark clock & PSU arrived in Australia last week, as did my Apogee Wyde-eye 75ohm BNC cable, and my EtherREGEN arrives tomorrow. Should we have bought a sine wave model OCXO clock and a filter instead? Or is the AfterDark Queen square wave output one of the ones that is done really well and (with good enough BNC cable) can match the sine wave output with filter at EtherREGEN?

I'm guessing I'm not alone in this situation or state of confusion.

Any feedback from AfterDark and Uptone would be appreciated as I'm not going to have a sine wave clock and filter to compare to.

Hi! Dsk6,

Thanks for your questions. We are quite confident this Queen Square Wave special version will surprise you with the performance it can made with the EtherREGEN.

The Giesemann Clock - Queen Square Wave Special Edition is special made by OCXO manufacture natively (OCXO module that has a built-in squarer circuit). So, there is no extra convertor outside the OCXO. This approach can make sure the OCXO can generate the best square wave for EtherREGEN.

We are planning to have "Trade-In"program for customer who wants to upgrade from Square Wave to Sine Wave Edition with the Mini - Circuit BLP -10.7+75 (75ohm version) . We want to make sure during the transition period after reading the white paper, we should provide more flexible option for audiophilestyle.com group buy.

The sine wave version is better quality OCXO in terms of Phase Noise and Allan Derivation on measurement. With the helps of the Mini - Circuit BLP -10.7+75 (75ohm version), it will enhance the performance much further in sounding according to the white paper.

P.S. The Emperor Signature to EVA is special grade product, they are in very limited supply each months. EVA is on waiting list about 30days.

Have a nice weekend.

Best Regards,

Adrian

AfterDark.

DSK6 · March 28, 2021

1 hour ago, AfterDark. said:

... The Giesemann Clock - Queen Square Wave Special Edition is special made by OCXO manufacture natively (OCXO module that has a built-in squarer circuit). So, there is no extra convertor outside the OCXO. This approach can make sure the OCXO can generate the best square wave for EtherREGEN.

We are planning to have "Trade-In"program for customer who wants to upgrade from Square Wave to Sine Wave Edition with the Mini - Circuit BLP -10.7+75 (75ohm version) . We want to make sure during the transition period after reading the white paper, we should provide more flexible option for audiophilestyle.com group buy.

The sine wave version is better quality OCXO in terms of Phase Noise and Allan Derivation on measurement. With the helps of the Mini - Circuit BLP -10.7+75 (75ohm version), it will enhance the performance much further in sounding according to the white paper. ...

Thanks Adrian and also Leo Sound. It is good to know that the squarer circuit is built in to the OCXO rather than being done off chip. Hopefully the OCXO module used is one of the "couple of chips that do this extremely well" as per Alex's earlier post.

Adrian, were your last 2 paragraphs that I quoted above comparing your sine wave versions to your Queen Square Wave SE version, or to the cheaper BG7TBL square wave clocks?

AfterDark. · March 28, 2021

6 hours ago, DSK6 said:

Thanks Adrian and also Leo Sound. It is good to know that the squarer circuit is built in to the OCXO rather than being done off chip. Hopefully the OCXO module used is one of the "couple of chips that do this extremely well" as per Alex's earlier post.

Adrian, were your last 2 paragraphs that I quoted above comparing your sine wave versions to your Queen Square Wave SE version, or to the cheaper BG7TBL square wave clocks?

Hi DSK6,

Thanks for your interested.

The quality of OCXO is determined by Phase Noise and Allan Derivation. All the Giesemann clock will have the above measurement tested directly on the BNC output. So it is a very accurate measurement with respect to all factors after going through the circuit inside.

We are comparing with Giesemann sine wave version to Queen Square Wave SE version according to their Phase Noise and Allan Derivation as well. The phase noise table @10Hz and @1Hz is the most sensitive areas, this figure will be useful for audiophile to choose their best clock with indicated measurement.

Have a nice weekend.

Best Regards,

Adrian

AfterDark.

ambre · March 28, 2021

5 hours ago, Superdad said:

It will. It's down a little more right at 10MHz (compared the 11MHz lowpass of the Mini-Circuits) but that should not be any problem. It is quite a steep filter. I thought the Crystek one was going to be a lot more expensive and a custom order item, but I see that Digikey has a few in stock for just $37 each.

Hi Superdad,

Agreed with Adrian for a 11Mhz MINI_CIRCUITS but would be nice to compare it with Crystek 10Mhz?

But yr remark quite steep filter. Is that better or worse ? Or just give it a try in real life?

Regards, Andreas

basillus · March 28, 2021

@Superdad
The 75 ohm BNC output of the BG7TBL will fit proberly with the the Mini - Circuit BLP -10.7 50 ohm?
It will not be a little loose/flimsy, because there is a difference in the thickness of the isolation in a 75 ohm and a 50 ohm BNC connector.

Superdad · March 28, 2021

6 hours ago, AfterDark. said:

We are comparing with Giesemann sine wave version to Queen Square Wave SE version according to their Phase Noise and Allan Derivation as well. The phase noise table @10Hz and @1Hz is the most sensitive areas, this figure will be useful for audiophile to choose their best clock with indicated measurement.

Hi Adrian:

While we are supportive of you new fine-value clock series, we ask that you (and others) keep conversations about AfterDark products in your own sponsored forum area or in one of the public forums.

We really prefer that this particular thread stay focused on the concepts and facts put forth in John’s paper.

Thank you,

—Alex C.

Superdad · March 28, 2021

48 minutes ago, basillus said:

@Superdad
The 75 ohm BNC output of the BG7TBL will fit proberly with the the Mini - Circuit BLP -10.7 50 ohm?
It will not be a little loose/flimsy, because there is a difference in the thickness of the isolation in a 75 ohm and a 50 ohm BNC connector.

They fit just fine. Nothing to worry about.

John Swenson tutoring paper: "Considerations regarding usage of external reference clocks" (EtherREGEN and other): Sine vs. square, impedance, cables—and a money saving surprise at the end.

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