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AK4499EQ - Best DAC ever
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Old 4th March 2021, 03:04 AM   #1481
Extreme_Boky is offline Extreme_Boky
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Quote:
Originally Posted by chris719 View Post
Two VCXO (implying PLL) and two small cheap XO that look to be the same frequency. All surrounding an Altera CPLD. Probably not up to the standards of the Jitterati.
The small ones will have lower phase noise than Crysteks... if NDK's in SDA or better flavour.
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Old 4th March 2021, 03:39 AM   #1482
chris719 is offline chris719  United States
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Still not good enough, apparently. Did you miss the last few pages of this thread?
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Old 4th March 2021, 08:24 AM   #1483
andrea_mori is offline andrea_mori  Italy
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Quote:
Originally Posted by chris719 View Post
Still not good enough, apparently. Did you miss the last few pages of this thread?
Again you don't understand, 4 poor oscillators become 2 good.

Just measure them with the FFT analyzer.
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Old 4th March 2021, 08:46 AM   #1484
chris719 is offline chris719  United States
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Wow, there is a PLL + VCXO and FIFO for SPDIF inputs. Who cares.

I thought you said that we need your clock with SC cut crystal hand-polished by virgins to get close-in phase noise that is acceptable.
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Old 4th March 2021, 09:22 AM   #1485
andrea_mori is offline andrea_mori  Italy
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Quote:
Originally Posted by chris719 View Post
Wow, there is a PLL + VCXO and FIFO for SPDIF inputs. Who cares.

I thought you said that we need your clock with SC cut crystal hand-polished by virgins to get close-in phase noise that is acceptable.
No, mine are good for satellite, GPS, radar but not for audio.

Indeed I'm selling my Timepod to buy an FFT analyzer.
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Old 4th March 2021, 12:24 PM   #1486
Markw4 is offline Markw4  United States
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Quote:
Originally Posted by Extreme_Boky View Post
The small ones will have lower phase noise than Crysteks... if NDK's in SDA or better flavour.
I'm not so sure. I have two pairs of 22/24MHz NDK SDA hand picked by Jocko (RIP). I haven't been able get them to sound as good as I can get with very carefully implemented Crysteks (used with AK4499). That was with Jocko's advice on how to use the NDK SDAs too.

Of course, maybe the Crysteks don't measure as well. If so, there must be something that is being missed about how clocks affect sound quality.

Last edited by Markw4; 4th March 2021 at 12:28 PM.
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Old 4th March 2021, 01:07 PM   #1487
laserscrape is offline laserscrape
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Have measurements of NDKs ever been published? NDK doesnt even include a spec in the datasheet which is an unusual choice if they really are better, aswell as cheaper, than the crysteks.
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Old 4th March 2021, 01:39 PM   #1488
Markw4 is offline Markw4  United States
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NDK has published graphs, but they don't guarantee all clocks meet that performance level. For one example, please see the attached.

There was also a graph that somebody made, not sure who. It showed NDK SDA having lower phase noise than Crystek. Without more information about how the graphs were obtained, I would take it with a grain of salt. I know that Crysteks are very sensitive to power and to buffering. They also take 3-days of power-on time to fully stabilize. It those things were not properly done when measurements were taken, then I personally wouldn't put much credence in it.
Attached Files
File Type: pdf ! NDK Audio DAC Clocks.pdf (146.9 KB, 18 views)

Last edited by Markw4; 4th March 2021 at 01:43 PM.
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Old 4th March 2021, 01:56 PM   #1489
Joseph K is offline Joseph K  Hungary
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Uhm.. I am not proud of this measurement, naturally I did try my presently available NDK (supposedly SDA) oscillayor. 'Presently' because I have assembled quite a number of dac's (Mirand) with it, - but did not had the tool to measure, yet.

There is dirt in the middle, I was experimenting with a LMH6702 buffer, plus the setup not optimized.

22,576MHz Fc

It is showing like - 83dBc/1Hz; - 114dBc/10Hz; - 144dBc/100Hz.

That is quite much compatible with either the NDK doc's blue curve, or the tests of Jocko (of selected SD oscillators..)
So for me, at least with this one random example, the quality and originality of the SDA clocks from Lorien, the group buy here in Diya, - is having one positive data point added..

Last edited by Joseph K; 4th March 2021 at 02:09 PM.
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