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Old 10th March 2009, 10:26 AM   #991
phofman is offline phofman  Czech Republic
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Quote:
Originally posted by 1audio
Originating the clock at the DAC is the right way but there is a bootstrap problem- the source needs to tell the dac what sample rate for the dac to switch the clocks, however there is no mechanism to do that in current products.
Yes, this is a major issue. It is possible to provide sample rate/volume support via serial port/I2C/ethernet (as an alsa-lib plugin or directly in the driver). E.g. there is a great alsa-lib plugin controling Arcam AVR via serial port (volume, balance, etc.). But there are no DACs supporting this.


Quote:
Originally posted by 1audio
With good shielding the soundcard should be a good digital source especially if noise impact on the clocks and output connections are minimized.
That is exactly the goal of my little project - a low-power network player with any quality PCI card physically separated from the little mainboard.

Quote:
Originally posted by 1audio
My biggest concern is that there isn't much happening in new soundcard chipset options that support all 6 sample rates. I hope Via will continue the Envy24 series. The others don't look as good and the Lynx /RME stuff has a whole lot of baggage not needed for 2 channel playback.
Yup, this is sad. I have yet to see a PCI express chip with both crystals. IIRC, there are some new PCIe cards with Envy24 and PCIe-PCI bridge. The 44.1kHz family is a matter of past and I am afraid manufacturers are not planning to mass produce PCIe pro-sumer cards with crystal 44.1kHz clock anymore. The PCI slot is a matter of past too, one must admire the bravery of Infrasonic (SIMS Corp.) to develop and market a brand-new PCI card these days.
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Old 10th March 2009, 11:24 AM   #992
Telstar is offline Telstar  Italy
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Quote:
Originally posted by phofman

Yup, this is sad. I have yet to see a PCI express chip with both crystals. IIRC, there are some new PCIe cards with Envy24 and PCIe-PCI bridge. The 44.1kHz family is a matter of past and I am afraid manufacturers are not planning to mass produce PCIe pro-sumer cards with crystal 44.1kHz clock anymore.
Besides being future-proof, I'm not sure anymore of the superiority of PCI for audio applications.
See here:
http://www.audioasylum.com/forums/pc...s/4/47769.html

Quote:
The PCI slot is a matter of past too, one must admire the bravery of Infrasonic (SIMS Corp.) to develop and market a brand-new PCI card these days.
It isn't so new. Auzentech got US distribution recently, but the Quartet has already been on the market for 3 years. I actually asked Auzentech if they are planning a pci-e version of the Quartet but got no reply (so far).
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Old 10th March 2009, 11:39 AM   #993
Telstar is offline Telstar  Italy
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Quote:
Originally posted by 1audio
Originating the clock at the DAC is the right way but there is a bootstrap problem- the source needs to tell the dac what sample rate for the dac to switch the clocks, however there is no mechanism to do that in current products.
A FPGA in the DAC should be able to detect the sample rate being served through spdif or i2s. And the DAC should slave the soundcard to itself.

How does these drivers look?
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Old 10th March 2009, 02:26 PM   #994
phofman is offline phofman  Czech Republic
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Quote:
Originally posted by Telstar
Besides being future-proof, I'm not sure anymore of the superiority of PCI for audio applications.
See here:
http://www.audioasylum.com/forums/pc...s/4/47769.html
Oh, again the story of low latency needed for quality playback. Yes low latency needed for MIDI/monitoring/mastering. Not so for pure playback. In fact the oposite - high latency - reduces interrupts, CPU load, danger of xruns, as the card reads larger chunks of data independantly without "bothering" the CPU.

In fact, I do not care much about the technology transmitting data between memory and I2S/whatever-format generator, as long as it provides sufficient reliable throughput, asynchronous feedback for flow control, the card features separate crystal clocks, and linux has reliable open source drivers for the key functions. It could as well be USB/FW, but still PCI cards seem to provide the best price/quality/performance ratio to me.


Quote:
Originally posted by Telstar
It isn't so new. Auzentech got US distribution recently, but the Quartet has already been on the market for 3 years. I actually asked Auzentech if they are planning a pci-e version of the Quartet but got no reply (so far).
Thanks for the info, I did not know that.
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Old 10th March 2009, 02:50 PM   #995
phofman is offline phofman  Czech Republic
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Quote:
Originally posted by Telstar
A FPGA in the DAC should be able to detect the sample rate being served through spdif or i2s. And the DAC should slave the soundcard to itself.
If the card is slaved to the DAC, its output sample rate will correspond to the incoming clock from the DAC.

The DAC clock must be changed first for the whole chain to move to another sample rate.
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Old 10th March 2009, 04:24 PM   #996
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Hi folks.

You're getting a bit off topic.
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Old 10th March 2009, 04:27 PM   #997
UnixMan is offline UnixMan  Europe
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Quote:
Originally posted by 1audio
UnixMan:
Can you post the pinout of the connection on the Juli@ card (since you seem to have figured it out)?

I have found it here:

I2S from Juli@ PCI sound card

as well as:

http://www.head-fi.org/forums/f46/ea...d-card-242285/
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Old 10th March 2009, 07:02 PM   #998
Telstar is offline Telstar  Italy
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Quote:
Originally posted by phofman


If the card is slaved to the DAC, its output sample rate will correspond to the incoming clock from the DAC.

The DAC clock must be changed first for the whole chain to move to another sample rate.
Because we're OT, could you send me an email? I have to ask you something about this.
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Old 10th March 2009, 11:48 PM   #999
UnixMan is offline UnixMan  Europe
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Quote:
Originally posted by Telstar

Because we're OT, could you send me an email? I have to ask you something about this.
I think there are many other people interested about that... (me, for one! ) so IMHO better open another thread instead.

BTW: another somewhat related thread you'd want to read: Pc -> Dac, How ?
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Old 11th March 2009, 11:45 AM   #1000
anbello is offline anbello  Italy
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Sorry just the last post a little bit OT.
Maybe not too much OT - i'am speaking of a linux box attached to an external dac with an spdif interface capable to slave the audio board in the box and so with the master clock on the dac.
What do you thing of the solution proposed on post #988?
Is it not interesting to you or not enough well explained?

If someone is interested i can open a new thread to talk about this stuff.

Ciao
Andrea
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