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.

[AfterDark.]

@Superdad

 

Hi! Alex,

 

Thanks for your edited white paper. I hope this information will help us to found their best 10M Master Clock for EtherREGEN.  We followed your white paper with all specifications. Not surprise our best seller now is Queen - square wave for EtherREGEN special edition. 

 

We did measure the clock with Phase Noise @1Hz / 10Hz with Allan Derivation plotted, with the Clock cable made from leading Suhner + Huber from Swiss, this cable is very high specification cable available in the market now. 

 

I believe most customer can enjoy the lowest phase noise to the circuit being clocked. 

 

Thanks again for make this white paper happened!!! 

 

Best Regards,

Adrian

AfterDark.

[AfterDark.]

10 hours ago, Superdad said:

Many of our friends here at Audiophile Style have been waiting for us to publish John Swenson's introductory explanations concerning choosing and implementing an external reference clock—be it for connection to an EtherREGEN or some other audio device.

 

[I take the blame for the delay. John gave me the first draft of his paper just over two months ago. The concepts were pretty clear but I think he wrote it late at night so it needed a few editing/formatting passes. I finally had time this past week to prepare it for presentation.]

 

Here is a link to the PDF for offline reading: Considerations regarding 10MHz external reference clocks...

And below are the JPGs of the pages.

 

We do not expect that this paper will answer all questions about the complex realm of high-frequency reference clocking, but it is a start. Nor does this paper get deeply technical and there are some generalizations.

 

After reading it, feel free to ask questions.

 

As teased in the thread title, at the end of the paper we present a shortcut to getting stellar performance out of less than state-of-the-art clocks.

If there is interest, we may begin stocking the item mentioned--mostly for convenience of our overseas clients as the company selling the small, inexpensive item charges $120 for shipping to destinations outside the USA.

 

Enjoy!

--Alex C.

===================

 

 

 

Hi! Alex,

 

We are receiving the BLP-10.7 + adaptor on next Mondy, and looking forward to test with our Giesemann Clock in sine wave. Really excited if this can unlock the potential for our Giesemann Clock to work with EtherREGEN. 

 

Thanks again.

 

Best Regards,

Adrian

AfterDark. 

 

 

[AfterDark.]

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. 

 

[AfterDark.]

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.