Master Clock for your EtherREGEN

[LowMidHigh]

2 hours ago, JohnSwenson said:

Given all this it is a wonder some people find this to improve things.  Given all the impedance mismatches the length of the cable is going to play an important part with square waves.

 

A telling example of how deep and wide expectations bias prevails in this hobby. 

[DarqueKnight]

14 minutes ago, LowMidHigh said:

A telling example of how deep and wide expectations bias prevails in this hobby. 

 

Not really a good example of audiophile expectation bias.

 

First, this clock is not an "audiophile" device.

 

Second, some of us, myself included, had very low expectations for this cheap clock. It was something I ordered out of curiosity.

 

Third, in my experience with this clock, in my system, the sine outputs sound inferior to the square wave outputs, with or without the highly recommended Mini-Circuits filter. If this clock was limited to sine wave outputs, I would not have had a positive experience with it.

[soares]

54 minutes ago, LowMidHigh said:

A telling example of how deep and wide expectations bias prevails in this hobby. 

No expectations from my side either. Perhaps I was one of the few lucky guys here. And yes the filter improved substantially my results. 

[R1200CL]

Well, let’s hope it’s possible to get some tip on how to modify it.

(John has already said how, but I’m not able to turn his introductions in to do it correctly). 

@Exocer Maybe you can help ?

[Rasputin]

5 hours ago, JohnSwenson said:

Now is a good time to write about what I found in the BG7TBL box that Alex sent me.

 

First off what is inside:

 

OCXO produces sine wave, this goes into a standard CMOS logic gate, which makes an attempt at converting the sine to square. This signal then feeds three more CMOS gates, one for each output. Outputs with sine have a multi-pole passive filter to get rid of most of the harmonics from the square waves. Square wave outputs just feed the CMOS gate output directly to the BNC jack.

 

An important thing to note is that standard CMOS outputs (such as these) cannot even come close to supplying enough current to feed a properly terminated  50 or 75 ohm input. The output impedance is also usually in the range of 10 to 20 ohms, which is not going to match anything.

 

So neither the sine nor square are actually close to outputting what they should, no matter what cable you use. If you get a good looking square wave out of one it is pure luck.

 

Look at the pictures of the square wave in a previous post, on the falling edge you can actually see a glitch where the falling actually goes back up, then back down. This is caused by an impedance mismatch on the board itself.

 

The 50 or 75 ohm output don't actually change the impedance coming out of the board, just the connector.

 

Given all this it is a wonder some people find this to improve things.  Given all the impedance mismatches the length of the cable is going to play an important part with square waves.

 

Getting a decent sound improvement out of this box is more a matter of luck than technical "goodness"  of any cables or connectors.

 

John S.

 

 

Thank you John,

Your conclusion correlates greatly with my results. With a very expensive bnc cable I was able to improve sq using the square output. With canare and other cheaper cables, ER sounded best without BG7TBL

[Exocer]

2 hours ago, R1200CL said:

Well, let’s hope it’s possible to get some tip on how to modify it.

(John has already said how, but I’m not able to turn his introductions in to do it correctly). 

@Exocer Maybe you can help ?

Actually - I am still trying to work this out. I have gone back and forth between the idea of doing away with the board completely and modifying the board. Either way, I will post about it once I figure it out :).

[MartinT]

The BG7TBL improves sound quality over the internal clocks of ER and Mutec. In my system, it always has, regardless of subsequent opinion.

[DarqueKnight]

22 minutes ago, MartinT said:

The BG7TBL improves sound quality over the internal clocks of ER and Mutec. In my system, it always has, regardless of subsequent opinion.

 

That's only because you got one of the good ones...and I got two of the good ones.

[R1200CL]

9 hours ago, DarqueKnight said:

Your BG7TBL uses a different OCXO (Frequency Communications) than mine (Symmetricom).

Do you know if data sheet is different ?

http://pmod27b6c.pic34.websiteonline.cn/upload/FE180datasheet.pdf

[LEO SOUND]

8 hours ago, Superdad said:

No it does not.

Which version of Afterdark do you have for testing? Queen Square wave 75 ohm?

[R1200CL]

Here is a bit OT about research on clocks. 

Maybe we can rent clock signals over the internet in the future. Fiber optic clocks is latest technology under developed. 
I would be happy if we’re getting optical transfer of OCXO clock signals one day. 

 

 

[pietka08]

10 hours ago, soares said:

Byłem zaskoczony ulepszeniem SQ, którego doświadczyłem. Głosy są naprawdę niesamowite. 

Excuse me, which filter are you referring to?

[GMG]

@Superdad  @JohnSwenson

thanks so much for all the time and effort to make sense of all the discussion around clocks. 
it does seem the OCXO is becoming a thing. Seeing more and more products that accept external clocks or implement on board OCXO. 
 

where would you say that an OCXO would make the most impact? Right before the DAC (with a reclocker for example) or up stream - at the ER or even further up at the music server (for example the new JCat network card that uses on board OCXO)

 

my intuition says that closer to the DAC is the first place to start and then work your way up stream, but maybe making sure the initial bit stream is as good as possible is a better approach?

 

thanks

 

[soares]

2 hours ago, pietka08 said:

Excuse me, which filter are you referring to?

[PYP]

3 hours ago, pietka08 said:

Excuse me, which filter are you referring to?

The filters (one for 50 ohm and one for 75 ohm) are mentioned at the end of John's tutoring paper (posting in case you missed it):  

[MartinT]

2 hours ago, GMG said:

where would you say that an OCXO would make the most impact? Right before the DAC (with a reclocker for example) or up stream - at the ER or even further up at the music server (for example the new JCat network card that uses on board OCXO)

 

As close to your DAC as you can get it. In my case, the Mutec (fed by the OCXO) is just before the DAC, connected with a very short AES cable, and gives it the best possible signal to work with.

[DarqueKnight]

10 hours ago, R1200CL said:

Do you know if data sheet is different ?

http://pmod27b6c.pic34.websiteonline.cn/upload/FE180datasheet.pdf

I do not have a data sheet for my Symmetricom OCXO. I recently asked both sellers of my BG7TBLs to ask their suppliers if they had a data sheet for the Symmetricom 159-00057-000/090-03861-13. I have not heard back from them.

 

As I mentioned in a previous post in this thread, an eBay seller posted a phase noise plot for the Symmetricom 159-00057-000/090-03861-13 and it showed -110 dBc/Hz at 1 Hz and -130 dBc/Hz at 10 Hz.

[pietka08]

My experience with BG7....
After a few months of listening with this clock, today I unplugged it from the system (lent it to a friend). I switched to the internal clock in ER and have been listening for about 4 hours now. Unfortunately the musicality, the pleasure of listening has disappeared somewhere. The sound is fine, but still something is missing, maybe it is just a matter of habit. I have already ordered Queen from AfterDark and I hope that the magic of musicality will return with redoubled force.

I use a rectangular wave :)

 

[Exocer]

51 minutes ago, DarqueKnight said:

I do not have a data sheet for my Symmetricom OCXO. I recently asked both sellers of my BG7TBLs to ask their suppliers if they had a data sheet for the Symmetricom 159-00057-000/090-03861-13. I have not heard back from them.

 

As I mentioned in a previous post in this thread, an eBay seller posted a phase noise plot for the Symmetricom 159-00057-000/090-03861-13 and it showed -110 dBc/Hz at 1 Hz and -130 dBc/Hz at 10 Hz.

 

I also saw other Ebay sellers state it is equivalent to the Morion MV200. Whether it was produced by Morion is unknown. Either way, I have switched my FE-180 for the symmetricom and it sounded terrible initially. So bad I had thought about re-installing the FE-180. Soundstage shrank, highs were shrill etc. Two days of warmup later and it sounded magical again. My ears nor my memory are good enough to confirm if it surpasses the FE-180 in an audible way. FWIW there are apparently multiple iterations of the MV200 with various phase noise specs.

[Clockmeister]

On 4/2/2021 at 6:27 AM, DarqueKnight said:

I have received my Mini-Circuits filters. The people at Mini-Circuits were a pleasure to deal with. The order was placed mid-morning and it was shipped early afternoon the same day. It arrived three days later by FedEx.

 

Figure 1. The filters arrived in a sturdy box with copious amounts of protective paper padding.

 

Figure 2. Two of the BLP-10.7-75+ 75 ohm filters and one of the BLP-10.7+ 50 ohm filters were ordered. I have one BG7TBL with three 75 ohm square wave outputs and another BG7TBL with a 75 ohm square wave output, a 75 ohm sine wave output, and a 50 ohm sine wave output.

 

Figure 3. I did not pay attention to the filter size on the spec sheet. I expected them to be smaller.

 

Figure 4. I also received this accessory for my Tektronix TDS 2012 oscilloscope. It is a 75 ohm feed through termination for impedance matching of 75 ohm cables to the scope's 1 M-ohm input impedance.

 

Figure 5. Three 75 ohm BNC cables. Bottom to top: Prosig PSG00542 RG-59/U coaxial cable, 2 meter length. This cable came with my dCS Puccini U-Clock word clock, cost $5, Revelation Audio Labs Prophecy Cryo-Silver with Oyaide BNC connectors, 1.5 meter length, made in 2009, cost $349, Revelation Audio Labs Prophecy Cryo-Silver with Furutech BNC connectors, 1 meter length, made in 2015, cost $449.

 

Figures 6 through 8 show the waveform and amplitude distortions that occurred due to the impedance mismatch between the cables and the scope. The BG7TBL had been on for over 24 hours prior to taking measurements.

 

Figure 6. Square wave pulse train waveform with Prosig cable, impedance mismatch.

 

Figure 7. Square wave pulse train waveform with RAL 2009 cable, impedance mismatch.

 

Figure 8. Square wave pulse train waveform with RAL 2015 cable, impedance mismatch.

 

Figure 9. Square wave pulse train waveform with Prosig cable, impedance matched.

 

Figure 10. Square wave pulse train waveform with RAL 2009 cable, impedance matched.

 

Figure 11. Square wave pulse train waveform with RAL 2015 cable, impedance matched.

 

Figure 12. Square wave pulse waveform with Prosig cable.

 

Figure 13. Square wave pulse waveform with RAL 2009 cable.

 

Figure 14. Square wave pulse waveform with RAL 2015 cable.

 

The RAL 2015 was the best sounding of the BNC cables.

 

Figure 15. Unfiltered sine wave from 75 ohm BG7TBL output.

 

Figure 16. Sine wave from 75 ohm BG7TBL output with 75 ohm Mini-circuits filter.

 

Listening Evaluations

 

Figure 17. EtherREGEN with Mini-Circuits 75 ohm filter at its clock input. Both the EtherREGEN and the BG7TBL clock were powered with separate TeraDak DC-30 linear power supplies.

 

I cannot speak for anyone else's EtherREGEN, but mine, and my ears, much preferred the BG7TBL's square wave input. Switching to the BG7TBL's 75 ohm sine wave input caused a loss of bass detail, diminished tactile sensation, and diminished imaging properties. Inserting the filter caused a further reduction in sound quality, particularly in bass detail.

 

While my results with the Mini-Circuits filter were not positive, I would not discourage anyone from trying it, especially if you have a high quality sine wave clock. Results will vary based on your clock and cables.

I  must admit  I am quite perplexed at the poor quality of signals shown here, (thanks for taking the time to do this DK) however what are you feeding the scope with the BG7TBL 10Mhz  or a Function Generator ?

 

If it s the clock I would be seriously looking at either how I was taking the measurements, the clock itself or a non taking into account reason.

 

Honesty chaps I never had any such variations even on a average clock with PN @65dBc???????

 

See first image of a 44.1Khz standard word clock output from a Mutec MC3+usb.

 

Measurements were taken 75Ohm RG45 cabling 1m, crimped 75 Ohm Digikey $8 connectors running into a genuine Lecroy PP090 electronic 75Ohm adapter using a 12bit HD Lecroy Oscilloscope. 

 

Also note we had conducted around 72 thousand full samples @ 5G/s

 

Second, third and fourth images are of a stock a Mutec ref10 master clock using the same identical 75Ohm transmission line, apologies I had a stock ref10 kicking about the lab today, normally it is an SE-120

 

Not sure what was going on with DK  screen images, perhaps a clear re-evaluation may help locate this issues?

 

 

[DarqueKnight]

 

 

1 hour ago, Clockmeister said:

I  must admit  I am quite perplexed at the poor quality of signals shown here, (thanks for taking the time to do this DK) however what are you feeding the scope with the BG7TBL 10Mhz  or a Function Generator ?

 

If it s the clock I would be seriously looking at either how I was taking the measurements, the clock itself or a non taking into account reason.

 

@Clockmeister

I do not understand why you would ask if the signals were from a function generator when I clearly stated that the signals were from the BG7TBL using three different 75 ohm cables.

 

You apparently missed @JohnSwenson's comments regarding the waveform quality of the BG7TBL's square wave output. I have quoted him below. Note the comments I highlighted in bold type.

 

21 hours ago, JohnSwenson said:

Now is a good time to write about what I found in the BG7TBL box that Alex sent me.

 

First off what is inside:

 

OCXO produces sine wave, this goes into a standard CMOS logic gate, which makes an attempt at converting the sine to square. This signal then feeds three more CMOS gates, one for each output. Outputs with sine have a multi-pole passive filter to get rid of most of the harmonics from the square waves. Square wave outputs just feed the CMOS gate output directly to the BNC jack.

 

An important thing to note is that standard CMOS outputs (such as these) cannot even come close to supplying enough current to feed a properly terminated  50 or 75 ohm input. The output impedance is also usually in the range of 10 to 20 ohms, which is not going to match anything.

 

So neither the sine nor square are actually close to outputting what they should, no matter what cable you use. If you get a good looking square wave out of one it is pure luck.

 

Look at the pictures of the square wave in a previous post, on the falling edge you can actually see a glitch where the falling actually goes back up, then back down. This is caused by an impedance mismatch on the board itself.

 

The 50 or 75 ohm output don't actually change the impedance coming out of the board, just the connector.

 

Given all this it is a wonder some people find this to improve things.  Given all the impedance mismatches the length of the cable is going to play an important part with square waves.

 

Getting a decent sound improvement out of this box is more a matter of luck than technical "goodness"  of any cables or connectors.

 

John S.

 

 

 

[Clockmeister]

DK

 

Apologies I did not see the full post.

 

We do have 10 or so of these clocks (different projects), and not one is so varied even with say 6 random cables I can pick from the pile test leads or commercial available audio cables. Although they are all powered via dedicated high quality DC sources

 

However all of these clocks are not used in IP improvement, all of our music is on board memory, we just slot in another 4TB on SSD or PCIE 5 (coming soon). The servers are purely storage only.

 

Streaming is a secondary source for day to day listening, for critical listening always FBA, when streaming comes of age will  embrace it, until then; I will take the path that works for ourselves.

 

 

 

[DarqueKnight]

Road Trip

 

I removed the triple square wave 75 ohm output BG7TBL from my home stereo system and evaluated it in my stereo system at work.

The sonic improvements were similar to those achieved at home.

 

In the home stereo system, the DAC and digital player are locked to a dCS Puccini word clock. I have not (yet) taken the Puccini word clock out of the chain and re-evaluated the BG7TBL's performance in that scenario. There is no master clock in the work stereo system.

 

Figure 1. Ready to travel: BG7TBL clock, TeraDak DC-30 linear power supply, Signal Cable 10 AWG 10 foot long power cord for, DC cable, Revelation Audio Labs Prophecy Cryo-Silver 75 ohm digital cable.

 

Figure 2. Office system, top to bottom: Bryston BDP-2 digital player, Bryston BDA-3 DAC, Bryston BP-26 preamplifier. At the left is a docked Dell VenuePro 7140 tablet computer used for controlling the BDP-2 digital player. The following components are under the desk: TeraDak DC-30 linear power supply for the EtherREGEN switch, TeraDak DC-150 linear power supply for the Synology DS718+ NAS, Synology DS718+, Bryston MPS-2 power supply for the Bryston BP-26 preamplifier, and PS Audio P10 AC regenerator. Loudspeakers are a pair of highly modified Polk Audio SDA CRS+ bookshelf speakers.

 

Figure 3. The EtherREGEN sits beind the Bryston equipment stack.

 

Figure 4: Office system BG7TBL evaluation setup.

 

Every aspect of stereophonic performance was enhanced by the addition of the BG7TBL: sound stage size, image weight, clarity, detail, bass articulation, tactile sensation, etc. The thing I appreciated the most was the improvement in detail at low listening levels. Assuming the AfterDark Giesemann clock works out in my home stereo system, the BG7TBL will be permanently reallocated to the work system.

 

[GMG]

Does anyone have a recommendation for reasonably priced multimeter scope that I can use to measure and see the waveform output of my clock?

And while I am at it I would also like to be able to see my mains waveform - see how noisy (or not) it is.

 

Will this work?

 

https://www.amazon.com/YEAPOOK-Handheld-Oscilloscope-Professional-Bandwidth/dp/B07XBL4BTL/ref=sr_1_2_sspa?crid=1VZZ3OSFUOL2D&dchild=1&keywords=multimeter+scope&qid=1617609321&sprefix=multime%2Caps%2C299&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFSNDZOUFNBUVBTRDMmZW5jcnlwdGVkSWQ9QTAxMjI5NzZRREw1OTJJNEY0RkImZW5jcnlwdGVkQWRJZD1BMDcyMzA0ODFEOVUxWkZJMEk2NTUmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

[DarqueKnight]

That scope will allow you to see the waveforms of your clock and mains power.

 

Measurement of mains noise content will require a scope with FFT function to allow you to see the harmonic content, or a scope that has power quality measurement features. There are also meters specifically for analyzing power quality. The good ones are not cheap.