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Old 14th March 2011, 05:11 PM   #161
exa065 is offline exa065  Canada
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After a long wait and much discussion exaU2I is now available for purchase! I apologize for the delay in getting the devices out to you. The price is $430 CAD. We are working around the clock to clear the backlog. Thank you for all your valuable input and patience.

The first batch is ready to be shipped out to those of you who received emails containing your Waiting List ID. We are going to send out more Waiting List IDs as soon as devices are produced, and we've chosen to do the shipments in this way in order to minimize the wait.

Meanwhile you can go to the website and look thought the user guide for more technical information. If you like what you see please consider signing up on the waiting list.
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Old 15th March 2011, 10:17 PM   #162
exa065 is offline exa065  Canada
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I've been notified that some Waiting List emails have been blocked by spam filters. If you are expecting an email with a Waiting List ID, please check your spam folder and add exa065@exadevices.com to your white list.
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Old 16th March 2011, 11:02 AM   #163
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Has any one already recieved its exa device?
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Old 17th March 2011, 02:07 AM   #164
exa065 is offline exa065  Canada
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Quote:
Originally Posted by AR2 View Post
Exa, here is one aspect that I am confused about.

In the system there should be only one master clock. If we look into one possible configuration, where there is an exa board and three two channel DACs (ESS 9012 or 9018) all on separate boards, what and how to deal with master clock? You explained earlier that your board will only allow to be configured as master unit, than what to do with DACs?
The concept of master clock is applicable when you have several "boxes". You should think of exaU2I as a part of your DAC. This is true when very short wires are used.

exaU2I should be the master clock for non-reclocking DACs.

Quote:
Originally Posted by AR2 View Post
Does that mean that clocks should be omitted from DAC boards and than master clock distributed from the exa board?
Yes. Only one master clock should be used. The situation is different for ES9018 and non-relocking DACs. When ES9018 is used, the master clock is actually the 100 MHz quartz on the DAC board. Ideally if you have 3 two channel DAC boards, they should clocked by only one 100 MHz quartz.

Quote:
Originally Posted by AR2 View Post
If that is the case should clock signal be buffered? Would your board allow for that since it demands to be master?
Yes, the board will allow buffering. If you need to you can use buffers. However the GMR isolators should be able to handle 3 DACs. If you decide to use buffers make sure that the cables are short. Only the clock interfaces may need buffering.

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Originally Posted by AR2 View Post
Does anyone knows if ESS chips allows to be switched from master to slave since they have a proprietary jitter reduction where signal entering chip is re-clocked. If switched from master to slave would that eliminate the benefit that chip offers in low jitter performance?
This is not exactly correct for ESS DACs. I am on non-disclosure and I can't be more specific. As I said, the master clock is the 100 MHz oscillator on the DAC board. This is the clock that is critical for low-jitter performance. ES9018 is powerful enough to cancel the very insignificant jitter caused by the exaU2I oscillators, the GMR isolators and a short cable.
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Old 17th March 2011, 02:39 AM   #165
exa065 is offline exa065  Canada
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Quote:
Originally Posted by Marek View Post
exa065,

did you make any measurements of real output jitter from your device?
Jitter is very difficult to measure. We don't have the best equipment, but we did jitter measurements. It makes sense to measure artifacts caused by jitter after the DAC if the DAC deploys jitter cancellation. Our ES9018 DAC board shows total noise due to Master Clock Jitter < -140dB.

In general I2S causes much less jitter than SP/DIF. exaU2I has a very clean I2S implementation.
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Old 17th March 2011, 03:51 AM   #166
rsdio is offline rsdio  United States
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Quote:
Originally Posted by exa065 View Post
The concept of master clock is applicable when you have several "boxes". You should think of exaU2I as a part of your DAC. This is true when very short wires are used.

exaU2I should be the master clock for non-recollecting DACs.
Mr. exa065 is absolutely correct here. With the exaU2I and a compatible DAC inside a single box, they are effectively operating "as one."

In fact, if you tear into several different high-end DAC units, you will probably find that nearly all of them have two separate circuit boards: One for the digital interface, and one for the analog conversion, with I2S or something similar between. So, a finished exaU2I setup is not any different from any other high-end DAC. It is actually far better to have two separate boards like this, even when the digital board is the master clock and the analog board with the DAC chip is slave. The advantages of two boards in terms of isolating digital noise from your audio far outweighs the slight challenge of having the clock cross between two boards. When the boards share a common power supply, especially with a common ground, and they are in the same enclosure, then there really is no reason to worry about which board is master, provided you don't do anything horribly wrong.
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Old 17th March 2011, 08:20 AM   #167
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What would be the best solution for wiring to a Buffalo II DAC ? (I2S wiring)

best regards,
Pepe
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Old 17th March 2011, 12:26 PM   #168
exa065 is offline exa065  Canada
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Quote:
Originally Posted by lindamar View Post
What would be the best solution for wiring to a Buffalo II DAC ? (I2S wiring)

best regards,
Pepe
Pepe,

See the Connection Example - Four Channel ES9018 in Quad Mode on the D.I.Y guide page: www.exadevices.com > exaU2I > D.I.Y. Guide. In this scenario every Buffalo kit will use its own master clock. Most likely there will be no problems. If your power supplies provide good decoupling between the Buffalos, there will be no interference between the 100 MHz clocks. If something goes wrong, you may hear a parasite signal in the audible range. You should be able to resolve it by altering the wiring, the distance between the DACs and the power supply filters. The best way to know is to try it.

The ideal solution would be to have one master 100MHz clock for all four Buffalos. May I ask the people that know well the Buffalo boards for help here?
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Old 17th March 2011, 01:04 PM   #169
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Than you for the explanation !

What about the cable type to use?.

Best regards
Pepe
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Old 17th March 2011, 03:34 PM   #170
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Quote:
Originally Posted by exa065 View Post
Jitter is very difficult to measure. We don't have the best equipment, but we did jitter measurements. It makes sense to measure artifacts caused by jitter after the DAC if the DAC deploys jitter cancellation. Our ES9018 DAC board shows total noise due to Master Clock Jitter < -140dB.

In general I2S causes much less jitter than SP/DIF. exaU2I has a very clean I2S implementation.
I thought the interest here was seeing the jitter performance without a jitter rejecting circuit in place. Like you'd see with a PCM1792/4 connected to the exaU21. O
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