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Post by MartinT on May 28, 2023 13:40:27 GMT
It might add a bit of jitter, being external, but to a worse baseline of the internal clock.
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Post by MikeMusic on May 28, 2023 14:41:17 GMT
Could it be analogue jitter ?  |
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Post by HD Music & Test on May 28, 2023 14:52:28 GMT
Analogue jitter, thats more amplifier's domain, that another discussion.
Forget the jitter figures, your clock is a slave master, it replaces the the Word clock (extracted from incoming serial data TDME or pcm) which is then re-assembled (lol) and use to supply the sync frame clock input ONLY.
What this is doing is causing the Serial Data & Bit clock to be more closely aligned, the closer these two are together the better (or closer) to the original signal it will become, so it has the effect of making the above data streams more desrible, IT has does not directly affected the internal clock performance, just replaced the sync refernce timing signal with a much more desirable one.
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Post by HD Music & Test on May 28, 2023 14:56:14 GMT
PCM is data stream of three components Serial (audio data) the bit clock and the frame sync (word clock) this is 'unpacked' at the recieve end (dac) and the word clock is extracted usually via a PLL and the then sent onto the dac chips (along with the bit & serial data TDME) so how good both the oscilliator and PLL clock recovery circuit are very important. I2s sends the clock signal sperately along with the rest of the data so its doesn't need to be unpacked but has its own issues to over come at the receive end
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Post by MartinT on May 28, 2023 15:02:52 GMT
I think the Gustard K-2 clock synth must rank highly in this regard. It's in the X26 Pro, R26 and A26.
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Post by John on May 28, 2023 16:32:23 GMT
Analogue jitter, thats more amplifier's domain, that another discussion. Forget the jitter figures, your clock is a slave master, it replaces the the Word clock (extracted from incoming serial data TDME or pcm) which is then re-assembled (lol) and use to supply the sync frame clock input ONLY. What this is doing is causing the Serial Data & Bit clock to be more closely aligned, the closer these two are together the better (or closer) to the original signal it will become, so it has the effect of making the above data streams more desrible, IT has does not directly affected the internal clock performance, just replaced the sync refernce timing signal with a much more desirable one. Thanks Tony |
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Post by stellabagpuss on May 28, 2023 20:43:29 GMT
Thanks Tony,that really helps to simplify alot of miss understanding of clocks and indeed jitter.
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Post by brettj on May 28, 2023 21:22:23 GMT
Late last year I bought an LHY 1 clock.
Fellas over on Head-Fi were noticing decent improvements into their DDC.
Bought, received, installed (with a Gustard C2 clock cable).
Run in for the month, as suggested.
First listen with the Audio GD DI-20HE; nothing different.
Hmmm. In the correct input? Audio GD on external clock?
Still, no earth shattering difference. Actually, no difference.
Tony was not overly impressed with it. Perhaps needs to be redesigned?
John (I think) found it unpleasant after an hour.
Found maybe the Audio GD doesn't improve significantly with clocks (at least the ones I can afford).
Tony also found that with a Leo Bodnar, and I think John/Damien with an external clock (maybe Damien's old After Dark).
There was a difference with a Mutec Ref10 SE120, but my funds, space, kit, ears, and desire are not up to that expense.
So, no clock on my list, at least while I have the Audio GD.
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Post by Clive on May 28, 2023 21:43:00 GMT
Thank you for the clock explanation Tony. That’s the first time I’ve seen the internal/external clock functions properly explained.
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Post by John on Jun 1, 2023 7:37:17 GMT
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Post by Clive on Jun 1, 2023 8:36:57 GMT
Good catch John. Some of his words are useful. What I take from this and what Tony has said is the the 10MHz clock is reference for the internal clock which is still in use…and as it’s for long term stability then a GPS synced clock seems like a good idea. Even with a DAC on its own connected with an external clock, we are hearing benefits. Perhaps this is unexpected but we hear it even if some think it shouldn’t happen. “A 10Mhz clock cannot be cleanly divided by 44.1khz or 48khz, and it cannot and does not directly run the DAC.
Instead, the DAC uses a PLL system with the 10Mhz clock as the input reference, to output a 49.1520/45.1584Mhz (or whatever the required rate is) using its OWN clock internally.
Your DACs clock is still the clock feeding the converter, it’s just being kept in time long term with the 10Mhz clock.
10Mhz clocks were never intended to improve jitter performance. They were intended to keep many devices in sync and prevent ‘clock drift’ over time in professional situations where you may have potentially dozens of DACs, ADCs, Processors etc running simultaneously and you do not want one to be running slower than the other and causing desync over time. As this could potentially cause issues in production or recording/outputting from several devices simultaneously.” |
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Post by MartinT on Jun 1, 2023 8:43:52 GMT
He is right in that the ESS DACs are running in current mode, so there is no distortion hump. I updated mine to the F20 firmware a long time ago.
He is so focussed on justifying his argument against external clocks because of poorer jitter performance from the PLL that he misses entirely the argument about low phase noise and spuriae. Why doesn't he just listen and then he'll get it?
Like you, John, I trust my own ears.
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Post by HD Music & Test on Jun 1, 2023 9:06:44 GMT
He has Martin & he is adament that its irrelivant, he was the same with DDC's however since moving (Golden sound the business) to a few miles for you and joining forces with the headfiers' the listening room has been garnered with liberal sprinklings of 'long term loan products' if you look back over the last 12 months of videos you may find certain products always seem to be in the back ground.
Recently I have seen minor admissions on DDC front, he not a bad lad really just likes running with the usual first prinicple techings.
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Tobias
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Post by Tobias on Jun 1, 2023 18:08:49 GMT
I respect Golden Sound and he seems like a smart pragmatic guy but he is also primarily a headphone and nearfield listener!
He doesn´t really seem to have much experience with a "real" speaker setup, from what I can tell.
For that reason I think he miss some aspects like soundstage and precis imaging (even if he does talk about such things) which is much more apparent on a speaker setup and closely connected to the timing, which is what the clock is impacting a lot, right?
That is a least my own thoughts and observation about Golden Sound.
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Post by MartinT on Jun 1, 2023 18:49:13 GMT
I respect Golden Sound and he seems like a smart pragmatic guy but he is also primarily a headphone and nearfield listener! He doesn´t really seem to have much experience with a "real" speaker setup, from what I can tell. For that reason I think he miss some aspects like soundstage and precis imaging (even if he does talk about such things) which is much more apparent on a speaker setup and closely connected to the timing, which is what the clock is impacting a lot, right? Good insight, Tobias. That does explain a few things. |
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Tobias
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Post by Tobias on Jun 1, 2023 19:30:18 GMT
I respect Golden Sound and he seems like a smart pragmatic guy but he is also primarily a headphone and nearfield listener! He doesn´t really seem to have much experience with a "real" speaker setup, from what I can tell. For that reason I think he miss some aspects like soundstage and precis imaging (even if he does talk about such things) which is much more apparent on a speaker setup and closely connected to the timing, which is what the clock is impacting a lot, right? Good insight, Tobias. That does explain a few things. I have followed him for a couple of years actually. What I think differs him from many other measurement focused headphone/desktop "listeners", is that he seems to be curious and willing to change his mind and not getting stuck in a corner. I can totally see him getting into proper HIFI loudspeaker setups and realizing that what he hear doesn´t go hand in hand with what he "knew" and explore why that is and make a video about that. He is somewhere in the middle, but on the headphone/desktop scene for sure, and has a lot of ASR enemies but also clearly not on the audiophile side either. |
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Post by MartinT on Jun 2, 2023 11:59:53 GMT
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Post by MartinT on Dec 29, 2023 17:35:48 GMT
As a follow-up to this external clock discussion, I have now taught myself a lesson twice over that the power supply for the external clock (in my case two AfterDarks) is of paramount importance. I cannot stress enough the importance of this. I thought a decent LPSU like the Zero Zone would be more than adequate. It isn't, not even nearly.
The Uptone JS-2, a choke regulated design, makes the AfterDarks sing like I've never heard before. I'm not saying it's good at everything, my experience is only with it powering clocks. However, in that application, it is epic and that appears to be as much the benign nature of the noise as the actual level of noise itself.
If you are using any type of external clock, take its power supply seriously. You may be as stunned as I have been.
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Post by HD Music & Test on Dec 29, 2023 18:22:01 GMT
I believe I have mentioned this on a few occasions lol
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Post by NigelB on Dec 29, 2023 22:30:43 GMT
We need to be clear here where we are deploying the clock, in addition to its accuracy or other parameters. In the bitstream world (streamer output, DAC etc), jitter affects sound quality. The closer to the DAC chip the clock is, the better, but even arch-digital guys dCS argue for the benefits of an external clock on their already class-leading DACs. It would appear that the separation of power supply, a separate case (RFI?) and perhaps a more accurate clock might outweigh the benefits of even their own highly accurate DAC-adjacent clock. In the ethernet world, jitter is a red herring; external clocks might improve sound quality if they have quiet circuitry and/or quiet power supplies, but ethernet clock accuracy won't (can't) affect sound quality as the data packets/frames get buffered, unpacked etc when they hit the DAC (a key role of a streamer is not only to control track selection etc but to convert ethernet data packets to bitstream). I used a Mutec MC3+ USB reclocker between my pimped Bluesound Node 2i and dCS Puccini (with external clock!). It made a real contribution to sound quality, despite the excellence of the DAC and clock it was feeding. I put this down to the poor clock within the otherwise excellent Node 2i, whicb has SPDIF output only so the timing is integrated into the music (data) signal. However, when I moved to an Innuos Zen Mini and matching Mk3 LPSU, the system sounded better without the Mutec; I put this down to the Innuos having a better internal clock than the Bluesound.
I would echo the comments above about the importance of a high quality (ie low noise) power supply.
Hope this helps, Nigel |
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