Recalculating the components value to get the Driscoll oscillator working at 10 MHz is not a problem, but the MOQ for the crystal required by the manufacturer is at least 10 pcs.
I hope there will be enough applicants.
A factory external watch is also available for my DAC (see Gustard C18 Audio Clock Preview) but I can't buy it now because of its price.
There is a big price difference, but what about the difference in the parameters of the two devices?
The difference is that the Gustard C18 is an OCXO so it implements a oven, while our oscillators does not implement the oven.
This means that the Gustard has better long term stability than our oscillators but usually long term stability does not matter in digital audio.
The most important feauture for audio application is the short term stability.
I have not found any phase noise plot of the Gustard C18 Audio Clock, they claim -110dBc at 1Hz from the carrier.
Although we have not yet built a 10 MHz oscillator you can assume a phase noise similar to the 11.2896 MHz one.
Both TWTMC-DRIXO and TWTMC-EXO perform 6dB better at 1Hz from the carrier than the Gustard (-116dBc and -116.9dBc).
This means that the Gustard has better long term stability than our oscillators but usually long term stability does not matter in digital audio.
The most important feauture for audio application is the short term stability.
I have not found any phase noise plot of the Gustard C18 Audio Clock, they claim -110dBc at 1Hz from the carrier.
Although we have not yet built a 10 MHz oscillator you can assume a phase noise similar to the 11.2896 MHz one.
Both TWTMC-DRIXO and TWTMC-EXO perform 6dB better at 1Hz from the carrier than the Gustard (-116dBc and -116.9dBc).
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+me.
And 5 or 100 MHz!
I would expect that a crystal manufacturer has these standard items
in the drawer, without an extra production run.
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Thank you for the short comparison. Please initiate a group buy. I need 2 pcs.
Hi gerhard,
Yes, in fact they are probably in continuous production runs. It would just be a matter of minimum quantities for an order. Shipped from stock.
I haven't any equipment that runs at 100 MHz, most old equipment will accept 1, 5 and 10 MHz inputs. Mine is pretty much all 10 MHz, and a couple will also accept 5 MHz.
Hi lasercut,
-Chris
Yes, in fact they are probably in continuous production runs. It would just be a matter of minimum quantities for an order. Shipped from stock.
I haven't any equipment that runs at 100 MHz, most old equipment will accept 1, 5 and 10 MHz inputs. Mine is pretty much all 10 MHz, and a couple will also accept 5 MHz.
Hi lasercut,
There are more ways to create other frequencies than using a PLL. And, with a 10 MHz xtal, that means you can use a commonly available external clock source. Freedom!
-Chris
If the C18 was designed to be used with the X26 PRO DAC then this DAC uses a PLL.
"The master clock of the ES9038PRO decoder chip built in X26pro is also controlled by the K2 high-precision lock synthesizer, which directly works in super-synchronous mode to synchronize ASRC re-sampling, and USB IIS AES coaxial optical fiber Bluetooth can also enjoy the improvement brought by local femtosecond or external 10M clock."
It looks like the ESS DAC chip works in true sync mode (internal DPLL bypassed) so the PLL has been implemented externally, so called K2.
"Tech Inside X26 PRO
X26 PRO uses a custom built high-quality femto-second clock generator which is integrated into a jitter reduction architecture. It does not require any Asynchronous Sample Rate Conversion solution to achieve this. Instead of going with an off-the-shelf, but high-quality crystal clock as Crystek and Accusilicon, Gustard designed their own Ultra-Low Noise PLL clock that is called K2."
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Yes, the X26 PRO is my DAC. If you are interested in measurement, take a look at the link Measurements of Gustard X26 Pro Dual 9038 Pro DAC | L7Audiolab
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I am very happy with the sound I am hearing. I do think though that one needs to question or at least acknowledge ones presumtions identifying opinion and not presenting it as fact.
long term stability does not matter in digital audio
In your opinion, or are there facts to back this up? I can't help but to expect that the ADC clock should match the DAC clock as closely as possible. Wouldn't any long term frequency difference between the two ultimately equate to the music being too fast or too slow? While most perhaps wouldn't recognize the difference I know some who are driven crazy by the pull up our down clock references 44.144 or 44.056 used for NTSC vs PAL conversion. Is there a specification for the maximum frequency drift over time or even for initial frequency accuracy tolerance of these clocks?
long term stability does not matter in digital audio
In your opinion, or are there facts to back this up? I can't help but to expect that the ADC clock should match the DAC clock as closely as possible. Wouldn't any long term frequency difference between the two ultimately equate to the music being too fast or too slow? While most perhaps wouldn't recognize the difference I know some who are driven crazy by the pull up our down clock references 44.144 or 44.056 used for NTSC vs PAL conversion. Is there a specification for the maximum frequency drift over time or even for initial frequency accuracy tolerance of these clocks?
I think there is video from Ted smith about it on YouTube, but the principle is that the human brain is more irritated from relative than from absolute change of speed (that seems kind of the reason that record players care more about consistency in speed than about exact absolute speed)
Not saying that this is absolute knowledge or proven but it makes sense from my experience and thinking. (Perhaps it is proven idk …)
I look at it like this: the absolute speed (e.g. how many seconds you will be wrong in one year) is not very important (of course can’t it be too bad, but cheap clocks are already quite good at this) as it is just an absolute change in pitch and speed, much more important for the listening experience seems to be consistency (close in phase noise).
As always ymmw
Greetings
Oli
Not saying that this is absolute knowledge or proven but it makes sense from my experience and thinking. (Perhaps it is proven idk …)
I look at it like this: the absolute speed (e.g. how many seconds you will be wrong in one year) is not very important (of course can’t it be too bad, but cheap clocks are already quite good at this) as it is just an absolute change in pitch and speed, much more important for the listening experience seems to be consistency (close in phase noise).
As always ymmw
Greetings
Oli
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Unless you had to synchronize the source the long term stability does not matter much.
I don't know if there is a specification for the maximum frequency drift over time but I believe the drift if so slow that you can't perceive it.
Hi Chris,
I will also get one piece to test the DRIXO and the EXO oscillators in order to validate the new component values specific for such frequency.
Therefore the total until now would be 7 pcs againt the MOQ of 10 pcs.
Andrea
I'd like to order the 10 Mhz SC cut crystal also. For now just 1, but will order 2 if its required to get over the ten item MOQ.
Andrea, I'm interested in getting the oscillator and STS boards that would have a 75 ohm output instead of the 50 ohm output. That's because the STS would input to a device that is rigidly set at 75 ohm input. Is that possible by just changing the RF transformers ordered that go with the boards?
Andrea, I'm interested in getting the oscillator and STS boards that would have a 75 ohm output instead of the 50 ohm output. That's because the STS would input to a device that is rigidly set at 75 ohm input. Is that possible by just changing the RF transformers ordered that go with the boards?