Master Clock Talk

[yukio1965]

Audio-Gd website clearly states that DI24 is better optimised for external clock use. DI25 reportedly is a functionality upgrade on DI24

Probably just because they have both 50 and 75 ohm input

 

[blackromek]

today I received ock 2s, I have a question about Harmonic Technology Digital Copper III cables, there are directional arrows on the cables, I connected the clock > device, is it correct?

 

[macrog]

today I received ock 2s, I have a question about Harmonic Technology Digital Copper III cables, there are directional arrows on the cables, I connected the clock > device, is it correct?

Yes arrows follow signal direction I.e. clock out on external clock to clock in on device

 

[blackromek]

I'll give the clock 12 hours of work and listen, I'm curious about the effect

 

[yukio1965]

I found an Afterdark Emperor Double Crown clock on the second hand market. The seller tells me it has a 50 ohm impedance but looking at the output connector I don't see the white plastic/teflon around the pin and therefore, most likely it will have a 75 ohm impedance. Do you think I can use it with the AudioGd Di20 interface which has a 50 ohm clock input? If so, should I use a 50 ohm cable or a 75 ohm one?

 

[MartinWT]

Do you think I can use it with the AudioGd Di20 interface which has a 50 ohm clock input? If so, should I use a 50 ohm cable or a 75 ohm one?

It doesn't matter at all as the AfterDarks output a sinewave clock (unless yours is a special). This means that cable shielding is critical and impedance doesn't matter at all. It's the opposite for squarewave clocks.

 

[sajunky]

I found an Afterdark Emperor Double Crown clock on the second hand market. The seller tells me it has a 50 ohm impedance but looking at the output connector I don't see the white plastic/teflon around the pin and therefore, most likely it will have a 75 ohm impedance. Do you think I can use it with the AudioGd Di20 interface which has a 50 ohm clock input? If so, should I use a 50 ohm cable or a 75 ohm one?

Measure resistance with multimeter, it will give an answer, connector is frequently wrong type.

 

[Jake2]

I recall much discussion on this thread a few years back without IIRC any particular resolution re the significance of the particular plugs incl dielectrics used for 75 vs 50 ohm impedance plug/socket combos. Cybershaft uses a single set of sockets with switchable impedance on its flagship clock so presumably gets comfortable the selected characteristic impedance of the transmission line - incl the internal cables and the BNC sockets and the external BNC cable that comprise it - is satisfactorily achieved by resistors etc that get toggled in and out.

Incidentally it may all be a moot point here as if you use Mutec’s Ref10 (which unlike Cybershaft does use different terminations for 50 vs 75 ohms) as a comparative visual reference, as it looks to me like thickness of the dielectric in the BNC socket of the AD clock pictured above more closely resembles the Mutec's 50ohm sockets than its 75ohm sockets…

 

[yukio1965]

I wrote to Afterdark and this is their answer.

"Yes, if there's no white plastic inside the connector, it's likely a 75-ohm impedance. You can still use it with a 50-ohm input; the mismatch impact is minimal."

So according to them even if it were to be a 75ohm I can use it with the 50ohm interface.

In your opinion how much would I lose in terms of sound?
Which cable would be better for me to use, a 50 ohm or a 75 ohm?

Could the output impedance of the clock be changed and how?

Last question.
What do you think in terms of overall quality (but also its quality/price ratio) of the Afterdark Emperor Double Crown clock?

 

[ray12345]

I am using a 75ohm Oyaide BNC cable on my 50Ohm Gustard X30 DAC. I have also previously used 50 ohm Harmonic Tech DC3. I would say the quality of the cable affects the sound more than whether it is 75 or 50 ohm.

Anyway, there are 75->50 ohm convertors, I used them now and it brings the vocals even more detailed now.

 

[MartinWT]

What do you think in terms of overall quality (but also its quality/price ratio) of the Afterdark Emperor Double Crown clock?

I have two AfterDark clocks, one King and one Emperor Triple Crown. They are excellent clocks, work reliably and give me outstanding sound quality.

As I said before, impedance doesn't matter with sinewaves. Make sure the clock cable is well shielded.

 

[blackromek]

Używam kabla Oyaide BNC 75 ohm z moim 50 ohm Gustard X30 DAC. Wcześniej używałem również 50 ohm Harmonic Tech DC3. Powiedziałbym, że jakość kabla ma większy wpływ na dźwięk niż to, czy jest 75 czy 50 ohm.

Tak czy inaczej, są tam przetworniki 75 -> 50 omów, których teraz użyłem i dzięki nim wokale stały się jeszcze bardziej szczegółowe.

Hello, I also have X30 and Harmonic Tech DC3 cables, so I need to think about a better cable? What clock are you using for x30? To be sure, I will ask if I connect lhy uip, lhy sw6 and X30 with Lhy Ock2s clock, then the clock option in x30 is set to external clock

 

[yukio1965]

@ray12345 I know that Cybershaft makes an impedance converter but that it works the opposite of what I need, that is, it is used to connect a clock with an output impedance of 50 ohms with an electronics that has an access impedance of 75 ohms.
Which converter do you use? Could you tell me the brand and model?
https://cybershaft.shop/products/50-ohm-matching-adapter

 

[Jake2]

Cybershaft comment here about the relative significance of impedance mismatches for sine vs square, consistent with J. Swenson’s view as mentioned by Martin above.

https://cybershaft.shop/products/75ohm-pure-silver-bnc-cable

Having said that if I was buying an external clock with only one output to be used for the critical asynchronous > synchronous conversion step (rather than ‘just’ asynchronous USB or Ethernet, though I rate those too!), then regardless of whether it was sine or square output I’d personally prioritise matching its impedance to my destination device for peace of mind, knowing I’d done my best to optimise things. If I was talking a multiple output clock for a mix of devices, some impedance matching, some not, I’d be more relaxed.

On the other hand if you can get a killer deal on a used clock some -3-5dBc/Hz @ 1Hz better performance than you can otherwise afford you should - I would hope - still be well ahead even after accounting for the purportedly negligible increase in low offset phase noise from impedance mismatches on a sine transmission line.

Addendum - FWIW Cybershaft themselves state in the instructions for their sine wave distributor/splitter it’s best to set output impedance to match the destination input impedance. https://cybershaft.shop/products/3-output-ultra-pure-clock-distributor-mc-dst05

Also - I like the fact that on their Japanese website (Google translated) they have phase noise and Allen deviation plots for the splitter -145dBc/Hz @1Hz! https://www.cybershaft.jp/a-products/clockdist05.html

 

[ray12345]

@ray12345 I know that Cybershaft makes an impedance converter but that it works the opposite of what I need, that is, it is used to connect a clock with an output impedance of 50 ohms with an electronics that has an access impedance of 75 ohms.
Which converter do you use? Could you tell me the brand and model?
https://cybershaft.shop/products/50-ohm-matching-adapter

I bought direct from Taobao. If you can't go through Taobao direct, I guess something like this also works :

https://www.aliexpress.com/item/325...huG4UAnh&utparam-url=scene:search|query_from: