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Old 24th February 2014, 08:49 PM   #891
1audio is online now 1audio  United States
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Having been down these roads here is what i found works-
Both USB (EMU 0404) and PCI interfaces work great over SPDIF. USB is less stable and can be sensitive to other USB traffic. The PCI interfaces are more solid (RME, EMU 1212 or ESI Juli@) are more robust. The TI PCM4222 demo board works pretty well, but its performance is not in the same league as the AKD5394A demo board. Making one from scratch looks really interesting but becomes quite the project. I know of two other efforts underway as well. I'm planning to make an upgrade card for the Juli@, but its on hold pending evaluation of the new AKM ADC.

In practice the master clock is locked to the external input and word clock, bit clock are "jam" synced to the external source. Essentially they are the decoded info from the AES stream. Probably not an issue for a single box.

Crystek has a variation of the CCHD-957 http://www.crystek.com/crystal/spec-...o/CVHD-957.pdf that is a VCXO.
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Old 24th February 2014, 09:07 PM   #892
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
Having been down these roads here is what i found works-
Both USB (EMU 0404) and PCI interfaces work great over SPDIF. USB is less stable and can be sensitive to other USB traffic. The PCI interfaces are more solid (RME, EMU 1212 or ESI Juli@) are more robust. The TI PCM4222 demo board works pretty well, but its performance is not in the same league as the AKD5394A demo board. Making one from scratch looks really interesting but becomes quite the project. I know of two other efforts underway as well. I'm planning to make an upgrade card for the Juli@, but its on hold pending evaluation of the new AKM ADC.

In practice the master clock is locked to the external input and word clock, bit clock are "jam" synced to the external source. Essentially they are the decoded info from the AES stream. Probably not an issue for a single box.

Crystek has a variation of the CCHD-957 http://www.crystek.com/crystal/spec-...o/CVHD-957.pdf that is a VCXO.
I saw the VCXO but the spec are not quite as good.

Maybe a better approach would be to get the USB streamer to work with a receiver. Then I can make the ADC board generic. The transmitter would be isolated with it's transformer or fiber. This would be less involved.

I have a 1212 here which I can dissect. I'll put together a jig to I/F with the USB streamer. This will answer my questions.
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Last edited by davada; 24th February 2014 at 09:11 PM.
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Old 24th February 2014, 09:15 PM   #893
JensH is offline JensH  Denmark
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Hi David,

Did you ever look at the information linked here:

QuantAsylum QA400

It does exactly what you seem to be looking for. If the whole thing has to be synchronized to a word clock that can be achieved e.g. with the Crystek VCXO (or two) and a PLL.
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Old 24th February 2014, 09:46 PM   #894
davada is offline davada  Canada
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Hi David,

Did you ever look at the information linked here:

QuantAsylum QA400

It does exactly what you seem to be looking for. If the whole thing has to be synchronized to a word clock that can be achieved e.g. with the Crystek VCXO (or two) and a PLL.
Yes I looked at it all but it's not quite what I'm after.
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Old 25th February 2014, 01:20 AM   #895
1audio is online now 1audio  United States
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Quote:
Originally Posted by davada View Post
I saw the VCXO but the spec are not quite as good.

Maybe a better approach would be to get the USB streamer to work with a receiver. Then I can make the ADC board generic. The transmitter would be isolated with it's transformer or fiber. This would be less involved.

I have a 1212 here which I can dissect. I'll put together a jig to I/F with the USB streamer. This will answer my questions.
Which version of the 1212 do you have? The EMU 1212 has spdif in and out and an analog interface to the 1010 card. Its also supposed to work with the 1616 or 1810 depending on version level. Are you going to use the analog i/o module (1010) to connect to the Minidsp or just add spdif i/o to the minidsp?

Modifying the 1010 is not difficult. I upgraded mine and it helped. I would do more but not sure its worth the effort. Its really good to start with. I need to reverse engineer more of the analog circuit.

I can't get my 1212 to talk to the 1616 and it seems to be the 1212. I use the cardbus interface and that works pretty well also.
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Old 25th February 2014, 02:17 AM   #896
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
Which version of the 1212 do you have? The EMU 1212 has spdif in and out and an analog interface to the 1010 card. Its also supposed to work with the 1616 or 1810 depending on version level. Are you going to use the analog i/o module (1010) to connect to the Minidsp or just add spdif i/o to the minidsp?

Modifying the 1010 is not difficult. I upgraded mine and it helped. I would do more but not sure its worth the effort. Its really good to start with. I need to reverse engineer more of the analog circuit.

I can't get my 1212 to talk to the 1616 and it seems to be the 1212. I use the cardbus interface and that works pretty well also.

Dick bought this off ebay but didn't like it. He sent it to me to play with.
The model numbers on the boards are EM8810 for the digital board and EM8820 for the analog/convertor board. What I have in mind in separate the boards. Put a header on a vero board and connect the USB streamer directly to the EMU analog board. That will give me the signals I need to evaluate both.

I can''t stand using the 1212 driver and software. Drive me nuts.

The receivers I've looked at run in I2S master mode. I might be able to connect the master clock from the streamer to the clock pin of the SPDIF receiver but I'm not sure that would work to sync the other clocks.

I can't imagine why miniDSP did it this way. The TOSlink input operates as a slave but only to 176kHz.

Come to think of it, I have a receiver mounted on a board from an old project done years ago. I try it with that as well.
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Old 25th February 2014, 04:35 AM   #897
davada is offline davada  Canada
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I found my answer at Planet Analog.

Planet Analog - Articles - SIGNAL CHAIN BASICS #54: In audio clocks, who's the boss, master, and slave?

The master clocks need to be at the same frequency.
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Old 25th February 2014, 07:25 AM   #898
1audio is online now 1audio  United States
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The driver UI is not easy. I got it stable by building an XP system from scratch for it. I'm getting pretty good performance from it.
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Old 25th February 2014, 03:28 PM   #899
davada is offline davada  Canada
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The driver UI is not easy. I got it stable by building an XP system from scratch for it. I'm getting pretty good performance from it.
The UI runs under XP ok for me but it's not graceful to try and change sample rates in ARTA and others with the UI. The UI protects the sample rate from being changed from outside apps. After all it is a recording system. I have to stop it, shut ARTA down, make the change in the UI and reopen ARTA. Then I have to match the sample rate in ARTA. After that it works great but what a hassle.

The reference article mentioned at the end of the link above is an excellent article for anyone embarking on building their own sampler. It's shows graphically what happens if...., what can go wrong and goes further making design recommendation. At the end there's a plug for their (the author's) technology but non the less.....

I'm thinking the USB streamer is unsuitable for an high performance ADC. I might be able to get it working with a receiver but any other way might end in disappointment. The best way to I/F two I2S running on there own clocks is to double buffer but that would require a processor to run the whole thing. Way to complicated and therefore not worth it.

I have settle with your conclusion Demain, SPDIF/AES or fiber into a PCI card with the same. The other possibility but more obscure is to use the 1394 port on the PC.

Is there an PCI digital audio I/O solution out there that doesn't have all the other sound card junk on it? Out of the sound cards any suggestions.
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Old 25th February 2014, 03:50 PM   #900
JensH is offline JensH  Denmark
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@David

What makes you think that the USBStreamer is unsuitable for a high performance ADC?
On its own perhaps, but not with a suitable interface, as I have described.

If you feel that I have overlooked something, please let me know.
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