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.

[flkin]

A few years ago when I was testing clocks and BNC cables I found that cables made a huge difference. So much so that getting a good clock without a good cable might be pointless. 
 

G, I Iistened to the Mutec Ref10 in my own system and the Habst digital BNC 5N cryo silver cable sounded by far the best. 
 

I’ve still got my old Cybershaft OP14 which is sine curved based and I’m curious how much this low pass filter will affect the sound. A filter is on the way now... 

[flkin]

Total noise = PM noise from total accumulated AM noise + PM noise from clock + PM noise from connection impedances

 

For a square wave, TN = 0 + PM noise from clock + PM noise from connection impedances

For a sine wave without filter, TN = PM noise from total accumulated AM noise + PM noise from clock + 0

For a sine wave and filter, TN = 0 + PM noise from clock + 0

 

Is the above summary correct?

 

In a nutshell, would it be fair to say then that using the filter makes the Sine wave clock work as well as the best square wave this particular sine wave clock can ever be? 

 

Separate questions - when using the filter gives a reduction in AM noise in the region of 0-70db, would using 2 filters further reduce the AM noise to 0-140db and make the drop after 11MHz steeper? 

[flkin]

56 minutes ago, LowMidHigh said:

 

That's from the bottom of the white paper:

 

"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 convertor, everything being just right inside the box—and you use a really low-attenuation-with-frequency cable."

I get that the best would be a well made square wave clock with good cables. Having experienced it, it’s really special when the clock setup is working well.

 

I’m trying to consider what a sine wave clock on a low pass filter would be like - would it be the same as the same sine wave clock with a square converter done properly along with impedance matched connectors.
 

 

[flkin]

I have to post a quick note of thanks for @JohnSwenson for thinking of and informing us about this low pass filter for sine wave clocks.

 

Although I didn't use it for my EtherRegen, it goes to show that the filters do work nicely.

 

I have a Cybershaft OP-14 which was part of my earlier Trifecta Stable system. I don't use it anymore since upgrading to a Pink Faun streamer but I was curious about the effect of the low pass filters on the clock. So I purchased 2 of them - the Crystek CLPFL-0010-BNC and the MiniCircuits BLP-10.7+.

 

I figured that if one worked, then perhaps 2 might be better. From their performance graphs the insertion loss was only 60-80db for some frequencies so  perhaps using 2 in series would make the slope steeper with better total attenuation.

 

It worked! Through a sMS-200neo (clocked by tx-USBultra) and a tx-USBultra reclocked by the Cybershaft with it’s Cybershaft branded 50ohm BNC cable, the sound is clearly better with the Crystek filter added and when the MiniCircuits filter was added in series, further improved.

 

From memory, it brought my trusty Cybershaft OP-14 up to possibly a Mutec clock or at the very least sounded like I added the expensive Habst ultra BNC cable.

 

So thanks for the tip, gratefully accepted. 😄