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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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35 minutes ago, DarqueKnight said:

No. I prefer neutral sounding gear. I do not own any tube gear.  The Prosig cable had the least clarity and detail.

 

You make me scratch my head.

 

Those cables don't transmit sound, merely an analog wave that triggers a gate on the receiving end, which is in turn controls the receiver's timing.  The less jitter and noise phase arriving over that analog wave, the more accurate the timing.  So why would a more jittery signal--e.g., Audio Labs, as per your tests--sound better than a cleaner signal?   

Stereo

[Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3]
Chain switchable to [Genelec 8331 x 2 + 7350]


Surround

[Genelec 1032C x 3 + 8431 x 2  + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] 

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1 hour ago, LowMidHigh said:

 

You make me scratch my head.

 

Those cables don't transmit sound, merely an analog wave that triggers a gate on the receiving end, which is in turn controls the receiver's timing.  The less jitter and noise phase arriving over that analog wave, the more accurate the timing.  So why would a more jittery signal--e.g., Audio Labs, as per your tests--sound better than a cleaner signal?   

I did not measure jitter and phase noise among the cables. I just looked at time domain plots on an oscilloscope.

 

If I understand you correctly, you are saying that the only electrical noise that affects sound quality at a DAC's output is jitter and phase noise? Why wouldn't an analog timing signal be subject to the same types of noise degradation as any other analog signal?

 

My digital music playback chain is as follows: NAS--(Ethernet)-->EtherREGEN--(Ethernet)-->Digital Music Player--(USB)-->Word Clock--(SPDIF)-->DAC.

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46 minutes ago, DarqueKnight said:

I did not measure jitter and phase noise among the cables. I just looked at time domain plots on an oscilloscope.

 

If I understand you correctly, you are saying that the only electrical noise that affects sound quality at a DAC's output is jitter and phase noise? Why wouldn't an analog timing signal be subject to the same types of noise degradation as any other analog signal?

 

My digital music playback chain is as follows: NAS--(Ethernet)-->EtherREGEN--(Ethernet)-->Digital Music Player--(USB)-->Word Clock--(SPDIF)-->DAC.

 

Here is what I’m saying:

 

As far as I understand, if the shape is not a perfect square, the triggering interval is flawed, thus jitter is introduced into the DAC.

 

Now, it could be that shielding on that cable is so terrible that it picks up noise, which countervails the nearly perfect square to a point where the overall sound is degraded. 

 

A bit off tangent, but somewhat related: money doesn’t necessarily buy quality in this game. I inquired with Furutech about the attenuation on some of their coax cables, and the figures sent back to me were pretty dismal; considerably worse than the more affordable Canare LV-77S. 

 

Stereo

[Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3]
Chain switchable to [Genelec 8331 x 2 + 7350]


Surround

[Genelec 1032C x 3 + 8431 x 2  + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] 

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4 hours ago, LowMidHigh said:

 

Here is what I’m saying:

 

As far as I understand, if the shape is not a perfect square, the triggering interval is flawed, thus jitter is introduced into the DAC.

 

Now, it could be that shielding on that cable is so terrible that it picks up noise, which countervails the nearly perfect square to a point where the overall sound is degraded. 

 

A bit off tangent, but somewhat related: money doesn’t necessarily buy quality in this game. I inquired with Furutech about the attenuation on some of their coax cables, and the figures sent back to me were pretty dismal; considerably worse than the more affordable Canare LV-77S. 

 

For my part, I made the choice of beginner to buy an OYAIDE DB-510 Digital Coaxial Cable BNC 75 Ohm Silver. Except that it is a very beautiful cable, I hope that this cable will bring me satisfaction and that its manufacture is serious.
Have you already tested this cable?

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4 hours ago, LowMidHigh said:

As far as I understand, if the shape is not a perfect square, the triggering interval is flawed, thus jitter is introduced into the DAC.

 

Sine waves aren't perfect square waves, and they make very good clock signals. A clock pulse can be any shape (square, sinusoidal, sawtooth, etc.) as long as it is periodic.

 

4 hours ago, LowMidHigh said:

Now, it could be that shielding on that cable is so terrible that it picks up noise, which countervails the nearly perfect square to a point where the overall sound is degraded.

 

I am not sure if you are making a general comment or if you are referring to a specific cable.

 

4 hours ago, LowMidHigh said:

A bit off tangent, but somewhat related: money doesn’t necessarily buy quality in this game.

 

I agree. That is true of a lot of merchandise categories.

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27 minutes ago, DarqueKnight said:

Sine waves aren't perfect square waves, and they make very good clock signals. A clock pulse can be any shape (square, sinusoidal, sawtooth, etc.) as long as it is periodic.

 

Matching the wave shape of the clock and the receiver will yield the best results, given the clocks in questions are of the same quality (that is, if you're comparing clocks), while a mismatch can introduce jitter into the receiver.  (In the case of the ER, the filter is here to address it) I believe the reason has to to do with the gate mechanism.  In your case, the cheap cable with the nearly perfect square should've produced the best sound, with the exception I'm making below. 

 

27 minutes ago, DarqueKnight said:

I am not sure if you are making a general comment or if you are referring to a specific cable.

 

I was referring to that stock cable, the less costly one, you tested with the square wave. One explanation I can come up with -- other than expectation bias, of course -- is that it picks up so much noise, that the benefits of the square wave are vitiated.  

 

Stereo

[Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3]
Chain switchable to [Genelec 8331 x 2 + 7350]


Surround

[Genelec 1032C x 3 + 8431 x 2  + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] 

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4 minutes ago, LowMidHigh said:

 In your case, the cheap cable with the nearly perfect square should've produced the best sound, with the exception I'm making below.

 

Yes. I expected the square waveforms to look sharper as I went up in cable quality.

 

4 minutes ago, LowMidHigh said:

I was referring to that stock cable, the less costly one, you tested with the square wave. One explanation I can come up with -- other than expectation bias, of course -- is that it picks up so much noise, that the benefits of the square wave are vitiated. 

 

I am actually somewhat of an audio cheapskate. My bias is toward spending the least amount of money to get the sound that I want.

 

I agree with your comment regarding noise effects on cable performance.

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Sound quality is going to be dependent on the consistency and noise at the exact trigger point threshold of the clock receiving equipment.  Whether the clock is square or sine doesn't matter at that level.  At the point of crossing the trigger point, how much jitter and phase noise there is superimposed on the signal (remember, it's an analogue signal) will count for a lot, because it will determine the amount of uncertainty.  Also, consistency from one crossing point to the next, which depends on the receiving circuit design.

TP-Link MR6400 4G router > Uptone EtherREGEN reclocker > Sonore Signature Rendu SE streamer > Gustard U18 DDC > Gustard X26 Pro DAC > Belles SA-100 power amp > Usher Dancer Be-20 speakers. AfterDark clocks x 2. PS Audio P3 & P10 regenerators.

https://theaudiostandard.net

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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? 

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1 hour ago, flkin said:

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? 

 

 

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."

Stereo

[Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3]
Chain switchable to [Genelec 8331 x 2 + 7350]


Surround

[Genelec 1032C x 3 + 8431 x 2  + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] 

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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.
 

 

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I can only say that sine with the filter sounds better than square with my BG7TBL clock.  Same (good) cables.

 

Not just a bit better - it's quite noticeable.

TP-Link MR6400 4G router > Uptone EtherREGEN reclocker > Sonore Signature Rendu SE streamer > Gustard U18 DDC > Gustard X26 Pro DAC > Belles SA-100 power amp > Usher Dancer Be-20 speakers. AfterDark clocks x 2. PS Audio P3 & P10 regenerators.

https://theaudiostandard.net

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3 hours ago, LowMidHigh said:

"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."

 

42 minutes ago, MartinT said:

I can only say that sine with the filter sounds better than square with my BG7TBL clock.  Same (good) cables.

Not just a bit better - it's quite noticeable.


There is nothing inconsistent between the above since as John’s examination of the BG7TBL’s circuits revealed, it does not at all qualify as having a “really good sine-square converter.”  It is actually quite poor in that regard. On the opposite side of the solar system in comparison to a Mutec REF10 for square wave performance.

 

Plus with the filter you don’t even have to sweat the cable quality (low attenuation for square; super shielding for sine). 9_9
 

Hence the sine output with filter is the way to go with this inexpensive clock. Heck, I bet the filter on the “squarish” wave output of BG7TBL is better than without even for those versions.

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2 hours ago, Superdad said:

Plus with the filter you don’t even have to sweat the cable quality (low attenuation for square; super shielding for sine). 9_9

Alex, 

What kind of shielding would be considered to be optimal for the sine cable?  Thanks. 

Grimm Audio MU1 > Mola Mola Tambaqui > Mola Mola Kaluga > B&W 803 D3    

Cables:  Kubala-Sosna    Power management:  Shunyata    Room:  Vicoustics  

 

“Nature is pleased with simplicity.”  Isaac Newton

"As neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man...they must be ranked among the most mysterious with which he is endowed."  Charles Darwin - The Descent of Man

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8 minutes ago, MartinT said:

That makes sense. The Belden 4694R cables are pretty well shielded and show it in the results.

 

Outer Shield Type Material Material Trade Name Coverage

Tape Tri-Laminate (Alum+Poly+Alum) Duobond® II 100%

Braid Tinned Copper (TC) 95%

Grimm Audio MU1 > Mola Mola Tambaqui > Mola Mola Kaluga > B&W 803 D3    

Cables:  Kubala-Sosna    Power management:  Shunyata    Room:  Vicoustics  

 

“Nature is pleased with simplicity.”  Isaac Newton

"As neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man...they must be ranked among the most mysterious with which he is endowed."  Charles Darwin - The Descent of Man

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I have tried the mini-circuits filter between my SOtM sCLK-OCX10 and the ER.  I am not hearing any improvement in SQ despite the SOtM being a sine wave clock, albeit an apparently very good one. 

 

Incidentally, I also tried the filter between the SOtM clock and the SOtM sms200 ultra Neo.  I would advise not testing this if you have these components - the sms200 did not work with the filter in place and worse, it didn’t work on the following power-up which was strange. It is fine again now though. But the experience makes me reluctant to try it again to double check. 

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55 minutes ago, roberto2 said:

Hello, I just received the Mini Circuits 75ohm filter. 

One stupid question: where do I install it? In one of the two sine wave output of the chinese clock or at the EtherRegen clock input?

eR input.  

Grimm Audio MU1 > Mola Mola Tambaqui > Mola Mola Kaluga > B&W 803 D3    

Cables:  Kubala-Sosna    Power management:  Shunyata    Room:  Vicoustics  

 

“Nature is pleased with simplicity.”  Isaac Newton

"As neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man...they must be ranked among the most mysterious with which he is endowed."  Charles Darwin - The Descent of Man

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  • 2 weeks later...

If I got it right, a better clock in general means less jitter. 
The thing that has me a bit confused is that I also understood that there is a thing called jitter rejection on the DAC - which I’m not quite sure I understand what it means - maybe it means the DAC is performing a reclocking process at its input?
So if I have a DAC that has been shown with measurements that it has near perfect jitter rejection would I ever benefit from a better clock up stream?

I’m not saying measurements are the only thing that matters, but if I should still expect to hear a different/better sound with an upstream clock, will it be due to less jitter or is there something else at play here?

 

@JohnSwenson I would appreciate your insight here. You mentioned to me in a different thread when I asked about adding a reclocker before the DAC, that some DACs will not benefit from a reclocker (especially if the DAC doesn’t have clock inputs). Would that be the same with upstream clocks?

 

for reference, my stream: router—>Optical rendu deluxe—>ER—>miniDSP shd studio—>Chord Qutest—>Naim Supernait2 + TeddyCap power upgrade. 

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